Functional fluids having low brookfield viscosity using high viscosity-index base stocks, base oils and lubricant compositions, and methods for their production and use

ABSTRACT

The present invention relates to functional fluids, especially automatic transmission fluids showing surprising low temperature Brookfield viscosities and methods to produce them.

This application is a Continuation-in-Part of U.S. Ser. No. 10/678,469filed Oct. 3, 2003 and U.S. Provisional Application No. 60/432,489 filedDec. 11, 2002.

FIELD OF THE INVENTION

This invention relates to base stocks and base oils that exhibit anunexpected combination of high viscosity index (130 or greater) and aratio of measured-to-theoretical high-shear/low-temperature viscosity at−30C or lower and the methods of making them. Specifically, the presentinvention relates to low-viscosity base stocks and base oils as used infunctional fluids. More specifically, the present invention relates toautomatic transmission fluids showing surprising low temperatureBrookfield viscosities and methods to produce them.

BACKGROUND OF THE INVENTION

API 1509 Appendix E defines base stocks (as opposed to base oils andlubricant compositions) as an hydrocarbon stream produced by a singlemanufacturer to the same specifications (independent of feed source ormanufacturers location) and that is identified by a unique formula,product identification number, or both. Base stocks may be manufacturedusing a variety of different processes including but not limited todistillation, solvent refining, hydrogen processing, oligomerization,esterification, and rerefining. Rerefined stock shall be substantiallyfree from materials introduced through manufacturing, contamination orprevious use. A base stock slate is a product line of base stocks thathave different viscosities but are in the same base stock grouping andfrom the same manufacturer. A base oil is the base stock or blend ofbase stocks used in formulated lubricant compositions. A lubricantcomposition may be a base stock, a base oil, either alone or mixed withother stocks, oils or functional additives.

Functional fluids comprise a broad range of lubricants that are used inautomotive and industrial hydraulic systems, automatic transmissions,power steering systems, shock absorber fluids, and the like. Thesefluids transmit and control power in mechanical systems, and thus musthave carefully controlled viscometric characteristics. In addition,these fluids may sometimes be formulated to provide multigradeperformance so as to ensure year round operation in variable climates.

Automatic Transmission Fluid (ATF) is one of the most common functionalfluids, and an integral part of all automatic transmissions. Automatictransmissions are used in about 80% to 90% of all vehicles in NorthAmerica and Japan and their use is becoming more commonplace in otherparts of the world. They are the most complex and costly sub-assembliesof a vehicle and the major OEMs have stringent specifications to controlall aspects of the components that go into their manufacture, includingthe functional fluid.

An ATF must have the right viscometrics at ambient start-uptemperatures, which can be as low as −40° C., while maintainingsufficient viscosity at higher operating temperatures of 100° C. ormore. ATF must also be oxidation stable since it is subjected to hightemperatures and is expected to remain in service for up to 100,000miles in some cases. In addition, frictional characteristics areimportant so as to provide smooth control of shifting with the clutchplates.

Great strides have been made in ATF additive formulation science to meetthese viscometric and oxidation requirements using solvent extractedmineral oils, commonly referred to as Group I base stocks. However, overthe past few years, with the increasing performance demands being madeon automatic transmission fluids, the use of hydrocracked base stocks,commonly referred to as Group II or Group III base stocks, have becomemore widespread. These base stocks give improved low temperatureperformance and longer oxidation life.

Previous OEM ATF requirements have usually been met solely by the use ofGroup I base stocks, or Group I base stocks mixed with small amounts ofGroup II or Group III base stocks. However most recently, the majorautomotive manufacturers have again increased the demands on ATFs bymoving to smaller and higher power-density designs that has increasedthe need for improved viscometrics. These new requirements have forcedthe industry to formulate ATF's almost completely from expensive GroupIII base stocks.

Tests used in describing lubricant compositions of this invention are:

-   -   (a) CCS viscosity measured by Cold Cranking Simulator Test (ASTM        D5293);    -   (b) Viscosity index (VI) measured by ASTM D2270;    -   (c) Theoretical viscosity calculated by Walther-MacCoull        equation (ASTM D341 appendix 1);    -   (d) Kinematic viscosity measured by ASTM D445    -   (e) Pour point as measured by ASTM D5950.    -   (f) Scanning Brookfield Viscosity as measured by ASTM D5133    -   (g) Brookfield Viscosity as measured by ASTM D2983.

The inventors note that the Walther-MacCoull equation of ASTM D341computes a theoretic kinematic viscosity, while the CCS reports anabsolute viscosity. To compute the ratio as used herein, the inventorsconverted the Walther-MacCoull viscosity as per equation (I).Theoretical viscosity@T ₁(° C.)=Walther-MacCoull Calculated KinematicViscosity@T ₁(° C.)×Density at T ₁(° C.)  (I)

-   -   where T₁ is the desired temperature.        The density at −35° C. is estimated from the density at 20° C.        using well-known formula. See, e.g., A. Bondi, “Physical        Chemistry of Lubricating Oils”, 1951, p. 5.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 graphically compares the measured CCS viscosities against thepredicted Walther-MacCoull viscosities at various temperatures.

FIG. 2 graphically compares the kinematic viscosity versus CCS viscosityfor various inventive oils and comparative examples.

FIG. 3 graphically illustrates Brookfield Viscosities versus the pourpoints for various lubricating oils.

SUMMARY OF THE INVENTION

This invention relates to base stocks and base oils that achieveimproved viscosity performance at low temperatures about −9° C.→−24° C.The present invention also relates to formulated functional fluids whichcomprise a base oil derived from waxy hydrocarbon feed stocks, eitherfrom natural or, mineral, or synthetic sources (e.g.Fischer-Tropsch-type processes), and which may be used to formulateATF's meeting the new industry Brookfield viscosity limits while stillable to employ a significant amount of Group II base stocks. Thisinvention also relates to processes or methods to make such base oils,base stocks, and formulated functional fluids and ATF's.

More specifically, this invention encompasses a functional fluidincorporating base stocks that have the surprising and unexpectedsimultaneous combination of properties of:

-   -   (a) viscosity index (VI) of 120 or greater,    -   (b) a pour point of about −9° C. to −24° C.,    -   (c) a ratio of measured-to-theoretical low-temperature viscosity        equal to 1.2 or less, at a temperature of −30C or lower, where        the measured viscosity is cold-crank simulator viscosity and        where theoretical viscosity is calculated at the same        temperature using the Walther-MacCoull equation.

Preferably, the base stocks and base oils of this invention as usedherein will have a measured-to-theoretical low-temperature viscosity ofabout 0.8 to about 1.2 at a temperature of −30C or lower, where themeasured viscosity is cold-crank simulator viscosity and wheretheoretical viscosity is calculated at the same temperature using theWalther-MacCoull equation

The base oil compositions of this invention encompass not onlyindividual base stocks as manufactured, but also mixtures or blends oftwo or more base stocks and/or base oils such that the resulting mixtureor blend satisfies the base stock requirements of this invention. Thebase oil compositions of this invention encompass a range of usefulviscosities, with base oil kinematic viscosity at 100 C of about 1.5 cStto 8.5 cSt, preferably about 2 cSt to 6 cSt, and more preferably about 3cSt to 5 cSt. The base oils of this invention encompasses a range ofuseful pour points, with pour points of about −9° C. to −24° C.,preferably about −12° C. to −24° C., and more preferably about −15° C.to about −24° C. In some instances, the pour point may range from −18°C. to −22° C.

The functional fluids of the present invention incorporate a base stockor base oils which may be produced by:

-   -   (a) hydrotreating a feedstock having a wax content of at least        about 50 wt. %, based on feedstock, with a hydrotreating        catalyst under effective hydrotreating conditions such that less        than 5 wt. % of the feedstock is converted to 650F (343C) minus        products to produce a hydrotreated feedstock whose VI increase        is less than 4 greater than the VI of the feedstock;    -   (b) stripping or distilling the hydrotreated feedstock to        separate gaseous from liquid product; and    -   (c) hydrodewaxing the liquid product with a dewaxing catalyst        which is at least one of ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57,        ferrierite, ECR-42, ITQ-13, MCM-68, MCM-71, beta, fluorided        alumina, silica-alumina or fluorided silica alumina under        catalytically effective hydrodewaxing conditions wherein the        dewaxing catalyst contains at least one Group 9 or Group 10        noble metal, and    -   (d) optionally, hydrofinishing the product from step (c) with a        mesoporous hydrofinishing catalyst from the M41S family under        hydrofinishing conditions.

Additionally, the base stocks and base oils incorporated into thefunctional fluids of this invention may have the following properties:

-   -   (a) saturates content of at least 90 wt %, and    -   (b) a sulfur content of 0.03 wt. % or less

Another embodiment of this invention encompasses a functional fluidcomprising:

-   -   (a) At least one base stock having a kinematic viscosity of        about 1.5 to about 8.5 mm²/sec at 100 C,    -   (b) A viscosity index of about 120 to 160,    -   (c) A pour point of about −9° C. to −24° C.,    -   (d) a saturates content of about 92 to 100%.

Performance additives as used in this invention may encompass, forexample, individual additives as components, combinations of one or moreindividual additives or components as additive systems, combinations ofone or more additives with one or more suitable diluent oils as additiveconcentrates or packages. Additive concentrate encompasses componentconcentrates as well as additive packages. Often in making orformulating lubricant compositions or functional fluids, viscositymodifiers or viscosity index improvers may be used individually ascomponents or concentrates, independent of the use of other performanceadditives in the form of components, concentrates, or packages.

Surprisingly the low measured-to-theoretical viscosity ratio, whichdistinguishes one unexpected performance advantage of the base stocksand base oils incorporated into this invention, can also be expected tobe observed at temperatures below −35C, for example down to −40C or evenlower. Thus at these low temperatures, actual viscosity of base stocksand base oils of this invention would be expected to approach thedesired, ideal, theoretical viscosity, while comparative base stocks andbase oils would be expected to deviate even more strongly away fromtheoretical viscosity (i.e. to higher measured-to-theoretical viscosityratios).

Viscosity index of the inventive base stocks and base oils incorporatedinto the present invention may be 120 or greater, or preferably 130 orgreater and in some instances, 140 or greater. The desired pour point ofthe inventive base stocks and base oils is about −9° C. to −24° C.,preferably −12° C. to −24° C., in some instances more preferably −15° C.to −24° C., or even −15° C. to −22° C. In some instances the pour pointmay be −18° C. to −22° C. For the inventive base stocks and base oils,the desired measured-to-theoretical ratio of low-temperature coldcranking simulator (CCS) viscosity equals about 1.2 or less, orpreferably about 1.16 or less, or more preferably about 1.12 or less.For the low-temperature viscosity profiles of the inventive base stocksand base oils, the desired inventive base stocks and base oils have CCSviscosity @−35C of less than 5500 cP, or preferably less than 5200 cP,or in some instances more preferably less than 5000 cP.

The highly advantageous low-temperature about −9° C. to −24° C.properties of these base stocks and base oils beneficially improve theperformance of finished functional fluids at concentrations of 20 vol %or greater of the total base stocks and base oils contained in suchcompositions. Preferably, the inventive functional fluids incorporatesthese base stocks and base oils in combination with other individualbase stocks and base oils to gain significant low-temperatureperformance benefits in finished lubricant compositions or functionalfluids. Preferably, these other base stocks and base oils may be used at50 vol % or more of the total base stocks and base oils contained informulated functional fluids, without detracting from the elements ofthis invention. And in certain instances, the other base oil(s) may bemost preferably used at 65 vol % or more of the total base stocks andbase oils, or even 80 vol % or more of the total base stocks and baseoils in finished lubricant compositions or functional fluids.

The inventors have made the unexpected finding that using the basestocks and base oils as described herein in a functional fluid allowsthe creation of a ATF exceeding the new OEM Brookfield Viscosity limitsfor ATF's

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to functional fluids and methods for optimizinglow temperature Brookfield viscosity of automatic transmission fluids.More particularly, the base oils incorporated into the functional fluidsof this invention have an unexpected of high viscosity index (120 orgreater) and a ratio of measured-to-theoreticalhigh-shear/low-temperature viscosity at −30C or lower that canadvantageously be used to formulate low-viscosity finished functionalfluids, specifically automatic transmission fluids (ATF's).

Automatic Transmission Fluid (ATF) is one of the most common functionalfluids, and an integral part of all automatic transmissions. Automatictransmissions are used in about 80% to 90% of all vehicles in NorthAmerica and Japan and their use is becoming more commonplace in otherparts of the world. They are the most complex and costly sub-assembliesof a vehicle and the major OEMs have stringent specifications to controlall aspects of the components that go into their manufacture, includingthe functional fluid.

An automatic transmission comprises a torque converter or clutchassembly, planetary gears, output drives and hydraulic system. The ATFacts as a hydraulic fluid to transfer power from the engine via thetorque converter or clutch assembly, and to actuate complex controls toengage the gears to give the correct vehicle speed.

ATF's must have the right viscometrics at ambient start-up temperatures,which can be as low as −40° C., while maintaining sufficient viscosityat higher operating temperatures of 100° C. or more. ATF must also beoxidation stable since it is subjected to high temperatures and isexpected to remain in service for up to 100,000 miles in some cases. Inaddition, frictional characteristics are important so as to providesmooth control of shifting with the clutch plates.

Great strides have been made in ATF additive formulation science to meetthese viscometric and oxidation requirements using solvent extractedmineral oils, commonly referred to as Group I base stocks. However, overthe past few years, with the increasing performance demands being madeon automatic transmission fluids, manufacturers have had to rely onhydrocracked base stocks, commonly referred to as Group II or Group IIIbase stocks, to meet the more stringent requirements.

Recently, the major automotive manufacturers have again increased therequired performance specifications for ATFs as they moved to smallerand higher power-density designs that has increased the need forimproved viscometrics. (See Table 1) In particular, lower viscosity atlower operating temperatures are required to ensure proper hydraulicoperation of the components. TABLE 1 Brookfield Viscosity Limits ofMajor OEM ATFs Previous Limits New or Pending Limits General Motors20,000 cP max 15,000 cP max Ford 20,000 cP max 13,000 cP max Chrysler22,000 cP max 10,000 cP max Toyota 20,000 cP max 15,000 cP max

Previous OEM ATF requirements have usually been met solely by the use ofGroup I base stocks, or Group I base stocks blended with of Group II orGroup III base stocks. These new stringent performance requirements canonly be met by formulating ATF's from the far more expensive Group IIIand Group IV base stocks.

The high viscosity index base stocks incorporated into the functionalfluids of this invention have superior low-temperature performance whencompared to other high viscosity index base stocks. The difference inperformance is most critical in the temperature range below −30C, whereconventional high viscosity index base stocks deviate significantly fromthe theoretical viscosity. To illustrate, measured low-temperature CCSviscosity of comparative conventional high viscosity index base stockstends to deviate to higher viscosity values than that predicted(Walther-MacCoull equation) for the expected theoretical viscosity ofthe same base stocks at low temperatures (FIG. 1).

The inventive base stocks, base oils incorporated into the functionalfluids of this invention surprisingly demonstrate the more ideal andhighly desirable performance predicted by the theoretical viscositybehavior of base stocks and base oils, as described according to theWalther-MacCoull equation (ASTM D341 appendix). In addition, the basestocks and base oils of this invention are found to be surprisinglydifferent from available commercial Group III base oil regarding theratio of measured-to-theoretical low-temperature viscosity, where actualviscosity is measured as cold cranking simulator (CCS) viscosity attemperatures of −30C or lower, and where theoretical viscosity derivesfrom the Walther-MacCoull equation (ASTM D341, appendix) at the sametemperature as the measured CCS viscosity. CCS viscosity is measuredunder high sheer conditions, whereas Brookfield viscosity is measuredunder low sheer conditions.

The base stocks and base oils incorporated into the functional fluids ofthis invention have the unique and highly desirable characteristic of ameasured-to-theoretical viscosity ratio of 1.2 or lower, preferably 1.16or lower, and in many instances more preferably 1.12 or lower. Basestocks and base oils having measured-to-theoretical viscosity ratios ofless than about 1.2 and with ratios approaching 1.0 are highlydesirable, because lower ratios indicate significant advantages inlow-temperature performance and operability. The currently availableGroup III base stocks and base oils, however, have characteristicmeasured-to-theoretical viscosity ratios of 1.2 and higher, indicatingpoorer base oil low-temperature viscosity and operability. In someinstances, it is preferred to have the measured-to-theoretical viscosityratio be between about 0.8 and about 1.2.

In one embodiment of this invention, the functional fluid of thisinvention incorporates a base stocks having the surprising andunexpected simultaneous combination of properties of:

-   -   (a) viscosity index (VI) of 120 or greater,    -   (b) a pour point of about −9° C. to −24° C.,    -   (c) a ratio of measured-to-theoretical low-temperature viscosity        equal to 1.2 or less, at a temperature of −30C or lower, where        the measured viscosity is cold-crank simulator viscosity and        where theoretical viscosity is calculated at the same        temperature using the Walther-MacCoull equation.

Additionally, the base stocks and base oils incorporated into thefunctional fluids of this invention may also have the followingproperties:

-   -   (a) saturates content of at least 90 wt %, and    -   (b) a sulfur content of 0.03 wt. % or less.

Products which incorporate the base stocks or base oils of thisinvention clearly have an advantage over other similar products madefrom conventional Group II and Group III base stocks. One embodiment ofthis invention is a formulated functional fluids comprising base stocksand base oils of this invention in combination with one or moreadditional co-base stocks and base oils. Another embodiment of thisinvention is a formulated functional fluids comprising base stocks andbase oils of this invention in combination with one or more performanceadditives. This invention is surprisingly advantageous in applicationswhere low-temperature properties are important to the performance of thefinished functional fluid. More specifically, the functional fluids ofthe present invention incorporating these base stocks or base oils havebeen found to produce ATF's with unexpectedly superior Brookfieldviscosity performance results.

Another embodiment of the present invention is a functional fluidcomprising:

-   -   (i) at least one base stock having a kinematic viscosity of        about 1.5 to about 8.5 mm²/sec at 100° C., preferably about 2.0        to about 6.0 mm²/sec at 100° C., more preferably about 3.0 to        about 5.0 mm²/sec at 100° C., a viscosity index of about 120 to        about 160, preferably about 120 to about 150, more preferably        about 130 to about 150, a pour point of about −9° C. to −24° C.,        preferably about −12° C. to −24° C., more preferably about        −15° C. to about −24° C., a saturates content of about 92 to        about 100 mass %, more preferably about 96 to about 100 mass %;        and    -   (ii) from about 50 vol % to about 80 vol %, preferably about 65        vol % to about 80 vol % of hydrocracked Group II or Group III        base stock mixture comprising one or more hydrocracked bases        stocks having a kinematic viscosity of about 1.5 to about 8.5        mm²/sec at 100° C., preferably about 1.5 to about 6.5 mm²/sec at        100° C., a viscosity index of about 90 or higher, a pour point        of about −15° C. maximum, a saturates content of about 92 to        about 100 mass %        -   wherein the inventive base stock (i) is present in an amount            of about 20 vol % to about 50 vol %, preferably about 20 vol            % to about 35 vol % of the base oil blend;        -   wherein the hydrocracked base stock (ii) is present in an            amount of about 50 vol % to about 80 vol %, preferably about            65 vol % to about 80 vol % of the base oil blend;        -   said mixture of base stocks having a base stock blend            kinematic viscosity of about 3 to about 6.5 mm²/sec at 100°            C., preferably about 3.5 mm²/sec to about 5.5 mm²/sec at            100° C., a viscosity index of about 100 to about 150,            preferably about 120 to about 150, a pour point of about            −12° C. maximum, preferably about −15° C. maximum; and    -   (iii) optionally, at least one performance additive;        -   wherein the functional fluid has a kinematic viscosity of            about 4.5 to about 9.5 mm²/sec at 100° C., preferably about            5.5 to about 8.5 mm²/sec at 100° C., a viscosity index of            about 150 to about 230, a pour point of about −42° C. or            less, and a Brookfield viscosity of about 15,000 cP or less            at −40° C., preferably about 13,000 cP or less at −40° C.,            more preferably about 10,000 cP or less at −40° C.            Process

The functional fluids that derive from incorporating the base stocks andbase oils produced by this processes demonstrate not only uniquecombinations of physical properties, but demonstrate uniquecompositional properties that distinguish and differentiate them fromavailable commercial products. Thus, the functional fluids incorporatingthe base stocks and base oils of this invention derived from theprocesses recited herein are expected to have unique chemical,compositional, molecular, and structural features that uniquely definethe base stocks and base oils of this invention.

The base stocks and base oils incorporated into the functional fluids ofthis invention are made according to processes comprising the conversionof waxy feedstocks to produce oils of lubricating viscosity having highviscosity indices and produced in high yields. Thus, one may obtain basestocks and base oils or base stocks having VIs of at least 120,preferably at least 130, more preferably at least 140, and havingexcellent low-temperature properties. These base stocks can be preparedin high yields while at the same time possessing excellent propertiessuch as high VI and low pour point.

The waxy feedstock used in these processes may derive from natural ormineral or synthetic sources. The feed to this process mays have a waxyparaffins content of at least 50% by weight, preferably at least 70% byweight, and more preferably at least 80% by weight. Preferred syntheticwaxy feedstocks generally have waxy paraffins content by weight of atleast 90 wt %, often at least 95 wt %, and in some instances at least 97wt %. In addition, the waxy feed stock used in these processes to makethe base stocks and base oils of this invention may comprise one or moreindividual natural, mineral, or synthetic waxy feedstocks, or anymixture thereof.

In addition, feedstocks to these processes may be either taken fromconventional mineral oils, or synthetic processes. For example,synthetic processes may include GTL (gas-to-liquids) or FT(Fischer-Tropsch) hydrocarbons produced by such processes as theFischer-Tropsch process or the Kolbel-Englehardt process. Many of thepreferred feedstocks are characterized as having predominantly saturated(paraffinic) compositions.

In more detail, the feedstock used in the process of the invention arewax-containing feeds that boil in the lubricating oil range, typicallyhaving a 10% distillation point greater than 650F (343C), measured byASTM D 86 or ASTM 2887, and are derived from mineral or syntheticsources. The wax content of the feedstock is at least about 50 wt. %,based on feedstock and can range up to 100 wt. % wax. The wax content ofa feed may be determined by nuclear magnetic resonance spectroscopy(ASTM D5292), by correlative ndM methods (ASTM D3238) or by solventmeans (ASTM D3235). The waxy feeds may be derived from a number ofsources such as natural or mineral or synthetic. In particular, waxyfeeds may include, for example, oils derived from solvent refiningprocesses such as raffinates, partially solvent dewaxed oils,deasphalted oils, distillates, vacuum gas oils, coker gas oils, slackwaxes, foots oils and the like, and Fischer-Tropsch waxes. Preferredfeeds are slack waxes and Fischer-Tropsch waxes. Slack waxes aretypically derived from hydrocarbon feeds by solvent or propane dewaxing.Slack waxes contain some residual oil and are typically deoiled. Footsoils are derived from deoiled slack waxes. The Fischer-Tropsch syntheticprocess prepares Fischer-Tropsch waxes. Non limiting examples ofsuitable waxy feedstocks include Paraflint 80 (a hydrogenatedFischer-Tropsch wax) and Shell MDS Waxy Raffinate (a hydrogenated andpartially isomerized middle distillate synthesis waxy raffinate.)

Feedstocks may have high contents of nitrogen- and sulfur-contaminants.Feeds containing up to 0.2 wt. % of nitrogen, based on feed and up to3.0 wt. % of sulfur can be processed in the present process. Feedshaving a high wax content typically have high viscosity indexes of up to200 or more. Sulfur and nitrogen contents may be measured by standardASTM methods D5453 and D4629, respectively.

For feeds derived from solvent extraction, the high boiling petroleumfractions from atmospheric distillation are sent to a vacuumdistillation unit, and the distillation fractions from this unit aresolvent extracted. The residue from vacuum distillation may bedeasphalted. The solvent extraction process selectively dissolves thearomatic components in an extract phase while leaving the moreparaffinic components in a raffinate phase. Naphthenes are distributedbetween the extract and raffinate phases. Typical solvents for solventextraction include phenol, furfural and N-methylpyrrolidone. Bycontrolling the solvent to oil ratio, extraction temperature and methodof contacting distillate to be extracted with solvent, one can controlthe degree of separation between the extract and raffinate phases.

Hydrotreating

For hydrotreating, the catalysts are those effective for hydrotreatingsuch as catalysts containing Group 6 metals (based on the IUPAC PeriodicTable format having Groups from 1 to 18), Groups 8-10 metals, andmixtures thereof. Preferred metals include nickel, tungsten, molybdenum,cobalt and mixtures thereof. These metals or mixtures of metals aretypically present as oxides or sulfides on refractory metal oxidesupports. The mixture of metals may also be present as bulk metalcatalysts wherein the amount of metal is 30 wt. % or greater, based oncatalyst. Suitable metal oxide supports include oxides such as silica,alumina, silica-aluminas or titania, preferably alumina. Preferredaluminas are porous aluminas such as gamma or beta. The amount ofmetals, either individually or in mixtures, ranges from about 0.5 to 35wt. %, based on the catalyst. In the case of preferred mixtures ofgroups 9-10 metals with group 6 metals, the groups 9-10 metals arepresent in amounts of from 0.5 to 5 wt. %, based on catalyst and thegroup 6 metals are present in amounts of from 5 to 30 wt. %. The amountsof metals may be measured by atomic absorption spectroscopy, inductivelycoupled plasma-atomic emission spectrometry or other methods specifiedby ASTM for individual metals.

The acidity of metal oxide supports can be controlled by addingpromoters and/or dopants, or by controlling the nature of the metaloxide support, e.g., by controlling the amount of silica incorporatedinto a silica-alumina support. Examples of promoters and/or dopantsinclude halogen, especially fluorine, phosphorus, boron, yttria,rare-earth oxides and magnesia. Promoters such as halogens generallyincrease the acidity of metal oxide supports while mildly basic dopantssuch as yttria or magnesia tend to decrease the acidity of suchsupports.

Hydrotreating conditions include temperatures of from 150 to 400° C.,preferably 200 to 350° C., a hydrogen partial pressure of from 1480 to20786 kPa (200 to 3000 psig), preferably 2859 to 13891 kPa (400 to 2000psig), a space velocity of from 0.1 to 10 liquid hourly space velocity(LHSV), preferably 0.1 to 5 LHSV, and a hydrogen to feed ratio of from89 to 1780 m³/m³ (500 to 10000 scf/B), preferably 178 to 890 m³/m³.

Hydrotreating reduces the amount of nitrogen- and sulfur-containingcontaminants to levels which will not unacceptably affect the dewaxingcatalyst in the subsequent dewaxing step. Also, there may be certainpolynuclear aromatic species which will pass through the present mildhydrotreating step. These contaminants, if present, will be removed in asubsequent hydrofinishing step.

During hydrotreating, less than 5 wt. % of the feedstock, preferablyless than 3 wt. %, more preferably less than 2 wt. %, is converted to650° F. (343° C.) minus products to produce a hydrotreated feedstockwhose VI increase is less than 4, preferably less than 3, morepreferably less than 2 greater than the VI of the feedstock. The highwax contents of the present feeds results in minimal VI increase duringthe hydrotreating step.

The hydrotreated feedstock may be passed directly to the dewaxing stepor preferably, stripped to remove gaseous contaminants such as hydrogensulfide and ammonia prior to dewaxing. Stripping can be by conventionalmeans such as flash drums or fractionators

Dewaxing Catalyst

The dewaxing catalyst may be either crystalline or amorphous.Crystalline materials are molecular sieves that contain at least one 10or 12 ring channel and may be based on aluminosilicates (zeolites) or onsilicoaluminophosphates (SAPOs). Zeolites used for oxygenate treatmentmay contain at least one 10 or 12 channel. Examples of such zeolitesinclude ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57, ferrierite, ITQ-13,MCM-68 and MCM-71. Examples of aluminophosphates containing at least one10 ring channel include ECR-42. Examples of molecular sieves containing12 ring channels include zeolite beta, and MCM-68. The molecular sievesare described in U.S. Pat. Nos. 5,246,566, 5,282,958, 4,975,177,4,397,827, 4,585,747, 5,075,269 and 4,440,871. MCM-68 is described inU.S. Pat. No. 6,310,265. MCM-71 and ITQ-13 are described in PCTpublished applications WO 0242207 and WO 0078677. ECR-42 is disclosed inU.S. Pat. No. 6,303,534. Preferred catalysts include ZSM-48, ZSM-22 andZSM-23. Especially preferred is ZSM-48. The molecular sieves arepreferably in the hydrogen form. Reduction can occur in situ during thedewaxing step itself or can occur ex situ in another vessel.

Amorphous dewaxing catalysts include alumina, fluorided alumina,silica-alumina, fluorided silica-alumina and silica-alumina doped withGroup 3 metals. Such catalysts are described for example in U.S. Pat.Nos. 4,900,707 and 6,383,366.

The dewaxing catalysts are bifunctional, i.e., they are loaded with ametal hydrogenation component, which is at least one Group 6 metal, atleast one Group 8-10 metal, or mixtures thereof. Preferred metals areGroups 9-10 metals. Especially preferred are Groups 9-10 noble metalssuch as Pt, Pd or mixtures thereof (based on the IUPAC Periodic Tableformat having Groups from 1 to 18). These metals are loaded at the rateof 0.1 to 30 wt. %, based on catalyst. Catalyst preparation and metalloading methods are described for example in U.S. Pat. No. 6,294,077,and include for example ion exchange and impregnation using decomposablemetal salts. Metal dispersion techniques and catalyst particle sizecontrol are described in U.S. Pat. No. 5,282,958. Catalysts with smallparticle size and well dispersed metal are preferred.

The molecular sieves are typically composited with binder materialswhich are resistant to high temperatures which may be employed underdewaxing conditions to form a finished dewaxing catalyst or may bebinderless (self bound). The binder materials are usually inorganicoxides such as silica, alumina, silica-aluminas, binary combinations ofsilicas with other metal oxides such as titania, magnesia, thoria,zirconia and the like and tertiary combinations of these oxides such assilica-alumina-thoria and silica-alumina magnesia. The amount ofmolecular sieve in the finished dewaxing catalyst is from 10 to 100,preferably 35 to 100 wt. %, based on catalyst. Such catalysts are formedby methods such spray drying, extrusion and the like. The dewaxingcatalyst may be used in the sulfided or unsulfided form, and ispreferably in the sulfided form.

Dewaxing conditions include temperatures of from 250-400° C., preferably275 to 350° C., pressures of from 791 to 20786 kPa (100 to 3000 psig),preferably 1480 to 17339 kPa (200 to 2500 psig), liquid hourly spacevelocities of from 0.1 to 10 hr⁻¹, preferably 0.1 to 5 hr⁻¹ and hydrogentreat gas rates from 45 to 1780 m³/m³ (250 to 10000 scf/B), preferably89 to 890 m³/m³ (500 to 5000 scf/B).

Hydrofinishing

At least a portion of the product from dewaxing is passed directly to ahydrofinishing step without disengagement. It is preferred tohydrofinish the product resulting from dewaxing in order to adjustproduct qualities to desired specifications. Hydrofinishing is a form ofmild hydrotreating directed to saturating any lube range olefins andresidual aromatics as well as to removing any remaining heteroatoms andcolor bodies. The post dewaxing hydrofinishing is usually carried out incascade with the dewaxing step. Generally the hydrofinishing will becarried out at temperatures from about 150° C. to 350° C., preferably180° C. to 250° C. Total pressures are typically from 2859 to 20786 kPa(about 400 to 3000 psig). Liquid hourly space velocity is typically from0.1 to 5 LHSV (hr⁻¹), preferably 0.5 to 3 hr⁻¹ and hydrogen treat gasrates of from 44.5 to 1780 m³/m³ (250 to 10,000 scf/B).

Hydrofinishing catalysts are those containing Group 6 metals (based onthe IUPAC Periodic Table format having Groups from 1 to, 18), Groups8-10 metals, and mixtures thereof. Preferred metals include at least onenoble metal having a strong hydrogenation function, especially platinum,palladium and mixtures thereof. The mixture of metals may also bepresent as bulk metal catalysts wherein the amount of metal is 30 wt. %or greater based on catalyst. Suitable metal oxide supports include lowacidic oxides such as silica, alumina, silica-aluminas or titania,preferably alumina. The preferred hydrofinishing catalysts for aromaticssaturation will comprise at least one metal having relatively stronghydrogenation function on a porous support. Typical support materialsinclude amorphous or crystalline oxide materials such as alumina,silica, and silica-alumina. The metal content of the catalyst is oftenas high as about 20 weight percent for non-noble metals. Noble metalsare usually present in amounts no greater than about 1 wt. %.

The hydrofinishing catalyst is preferably a mesoporous materialbelonging to the M41S class or family of catalysts. The M41S family ofcatalysts are mesoporous materials having high silica contents whosepreparation is further described in J. Amer. Chem. Soc., 1992, 114,10834. Examples included MCM-41, MCM-48 and MCM-50. Mesoporous refers tocatalysts having pore sizes from 15 to 100 Å. A preferred member of thisclass is MCM-41 whose preparation is described in U.S. Pat. No.5,098,684. MCM-41 is an inorganic, porous, non-layered phase having ahexagonal arrangement of uniformly-sized pores. The physical structureof MCM-41 is like a bundle of straws wherein the opening of the straws(the cell diameter of the pores) ranges from 15 to 100 Angstroms. MCM-48has a cubic symmetry and is described for example is U.S. Pat. No.5,198,203 whereas MCM-50 has a lamellar structure. MCM-41 can be madewith different size pore openings in the mesoporous range. Themesoporous materials may bear a metal hydrogenation component which isat least one of Group 8, Group 9 or Group 10 metals. Preferred are noblemetals, especially Group 10 noble metals, most preferably Pt, Pd ormixtures thereof.

Generally the hydrofinishing will be carried out at temperatures fromabout 150° C. to 350° C., preferably 180° C. to 250° C. Total pressuresare typically from 2859 to 20786 kPa (about 400 to 3000 psig). Liquidhourly space velocity is typically from 0.1 to 5 LHSV (hr⁻¹), preferably0.5 to 3 hr⁻¹ and hydrogen treat gas rates of from 44.5 to 1780 m³/m³(250 to 10,000 scf/B).

In one embodiment, the present invention is directed to a functionalfluid comprising at least one base stock with a VI preferably of atleast 130 produced by a process which comprises:

(1) hydrotreating a feedstock having a wax content of at least about 60wt. %, based on feedstock, with a hydrotreating catalyst under effectivehydrotreating conditions such that less than 5 wt. % of the feedstock isconverted to 650° F. (343° C.) minus products to produce a hydrotreatedfeedstock whose VI increase is less than 4 greater than the VI of thefeedstock;

(2) stripping the hydrotreated feedstock to separate gaseous from liquidproduct; and

(3) hydrodewaxing the liquid product with a dewaxing catalyst which isat least one of ZSM-48, ZSM-57, ZSM-23, ZSM-22, ZSM-35, ferrierite,ECR-42, ITQ-13, MCM-71, MCM-68, beta, fluorided alumina, silica-aluminaor fluorided silica alumina under catalytically effective hydrodewaxingconditions wherein the dewaxing catalyst contains at least one Group 9or Group 10 noble metal.

Another embodiment of the present invention is directed to a functionalfluid at least one base stock with a VI preferably of at least 130produced by a process which comprises:

(1) hydrotreating a lubricating oil feedstock having a wax content of atleast about 50 wt. %, based on feedstock, with a hydrotreating catalystunder effective hydrotreating conditions such that less than 5 wt. % ofthe feedstock is converted to 650° F. (343° C.) minus products toproduce a hydrotreated feedstock to produce a hydrotreated feedstockwhose VI increase is less than 4 greater than the VI of the feedstock;

(2) stripping the hydrotreated feedstock to separate gaseous from liquidproduct;

(3) hydrodewaxing the liquid product with a dewaxing catalyst which isat least one of ZSM-22, ZSM-23, ZSM-35, ferrierite, ZSM-48, ZSM-57,ECR-42, ITQ-13, MCM-68, MCM-71, beta, fluorided alumina, silica-aluminaor fluorided silica-alumina under catalytically effective hydrodewaxingconditions wherein the dewaxing catalyst contains at least one Group 9or 10 noble metal; and

(4) hydrofinishing the product from step (3) with a mesoporoushydrofinishing catalyst from the M41S family under hydrofinishingconditions.

Another embodiment of the present invention is directed to a functionalfluid comprising at least one base stock with a VI preferably of atleast 130 produced by a process which comprises:

(1) hydrotreating a lubricating oil feedstock having a wax content of atleast about 60 wt. %, based on feedstock, with a hydrotreating catalystunder effective hydrotreating conditions such that less than 5 wt. % ofthe feedstock is converted to 650° F. (343° C.) minus products toproduce a hydrotreated feedstock to produce a hydrotreated feedstockwhose VI increase is less than 4 greater than the VI of the feedstock;

(2) stripping the hydrotreated feedstock to separate gaseous from liquidproduct;

(3) hydrodewaxing the liquid product with a dewaxing catalyst which isZSM-48 under catalytically effective hydrodewaxing conditions whereinthe dewaxing catalyst contains at least one Group 9 or 10 noble metal;and

-   -   (a) Optionally, hydrofinishing the product from step (3) with        MCM-41 under hydrofinishing conditions.        Additional details concerning the processes that make the        current invention may be found in co-pending application U.S.        Ser. No. 60/416,865 which is hereby incorporated by reference in        its entirety.        Base Stocks and Base Oils

A wide range of base stocks and base oils are known in the art. Basestocks and base oils that may be used as co-base stocks or co-base oilsin combination to incorporated into functional fluids of the presentinvention along with the unique base stocks and base oils describedherein are natural oils, mineral oils, and synthetic oils. Theselubricant base stocks and base oils may be used individually or in anycombination of mixtures with the instant invention. Natural, mineral,and synthetic oils (or mixtures thereof) may be used unrefined, refined,or rerefined (the latter is also known as reclaimed or reprocessed oil).Unrefined oils are those obtained directly from a natural, mineral, orsynthetic source and used without added purification. These includeshale oil obtained directly from retorting operations, petroleum oilobtained directly from primary distillation, and ester oil obtaineddirectly from an esterification process. Refined oils are similar to theoils discussed for unrefined oils except refined oils are subjected toone or more purification steps to improve the at least one lubricatingoil property. One skilled in the art is familiar with many purificationprocesses. These processes include for example solvent extraction,distillation, secondary distillation, acid extraction, base extraction,filtration, percolation, dewaxing, hydroisomerization, hydrocracking,hydrofinishing, and others. Rerefined oils are obtained by processesanalogous to refined oils but using an oil that has been previouslyused.

Groups I, II, III, IV and V are broad categories of base oil stocksdeveloped and defined by the American Petroleum Institute (APIPublication 1509; www.API.org) to create guidelines for lubricant basestocks and base oils. Group I base stock generally have a viscosityindex of between about 80 to 120 and contains greater than about 0.03 wt% sulfur and/or less than about 90% saturates. Group II base stocksgenerally have a viscosity index of between about 80 to 120, and containless than or equal to about 0.03 wt % sulfur and greater than or equalto about 90% saturates. Group III stock generally has a viscosity indexgreater than about 120 and contain less than or equal to about 0.03 wt %sulfur and greater than about 90% saturates. Group IV includespolyalphaolefins (PAO). Group V base stock includes base stocks notincluded in Groups I-IV. Table 2 below summarizes properties of each ofthese five Groups. TABLE 2 API Classification of Base stocks and baseoils Saturates (wt %) Sulfur (wt %) Viscosity Index Group I <90&/or >0.03% & ≧80 & <120 Group II ≧90 & ≦0.03% & ≧80 & <120 Group III≧90 & ≦0.03% & ≧120 Group IV Polyalphaolefins (PAO) Group V All otherbase stocks and base oils not included in Groups I, II, III, or IV

Base stocks and base oils may be derived from many sources. Natural oilsinclude animal oils, vegetable oils (castor oil and lard oil, forexample), and mineral oils. In regard to animal and vegetable oils,those possessing favorable thermal oxidative stability can be used. Ofthe natural oils, mineral oils are preferred. Mineral oils vary widelyas to their crude source, for example, as to whether they areparaffinic, naphthenic, or mixed paraffinic-naphthenic. Oils derivedfrom coal or shale are also useful in the present invention. Naturaloils vary also as to the method used for their production andpurification, for example, their distillation range and whether they arestraight run or cracked, hydrorefined, or solvent extracted.

Synthetic oils include hydrocarbon oil. Hydrocarbon oils include oilssuch as polymerized and interpolymerized olefins (polybutylenes,polypropylenes, propylene isobutylene copolymers, ethylene-olefincopolymers, and ethylene-alphaolefin copolymers, polymers or copolymerof hydrocarbyl-substituted olefins where hydrocarbyl optionally containsO, N, or S, for example). Polyalphaolefin (PAO) oil base stocks are acommonly used synthetic hydrocarbon oil. By way of example, PAOs derivedfrom C8, C10, C12, C14 olefins or mixtures thereof may be utilized. SeeU.S. Pat. Nos. 4,956,122; 4,827,064; and 4,827,073, which areincorporated herein by reference in their entirety.

Group III and PAO base stocks and base oils are typically available in anumber of viscosity grades, for example, with kinematic viscosity at 100C of 4 cSt, 5 cSt, 6 cSt, 8 cSt, 10 cSt, 12 cSt, 40 cSt, 100 cSt, andhigher, as well as any number of intermediate viscosity grades. Inaddition, PAO base stocks and base oils with high viscosity-indexcharacteristics are available, typically in higher viscosity grades, forexample, with kinematic viscosity at 100 C of 100 cSt to 3000 cSt orhigher. The number average molecular weights of the PAOs, which areknown materials and generally available on a major commercial scale fromsuppliers such as ExxonMobil Chemical Company, Chevron-Phillips,BP-Amoco, and others, typically vary from about 250 to about 3000. ThePAOs are typically comprised of relatively low molecular weighthydrogenated polymers or oligomers of alphaolefins which include, butare not limited to, C2 to about C32 alphaolefins with C8 to about C16alphaolefins, such as 1-octene, 1-decene, 1-dodecene and the like, beingpreferred. The preferred polyalphaolefins are poly-1-octene,poly-1-decene and poly-1-dodecene and mixtures thereof and mixedolefin-derived polyolefins. However, the dimers of higher olefins in therange of C14 to C18 may be used to provide low viscosity basestocks ofacceptably low volatility. Depending on the viscosity grade and thestarting oligomer, the PAOs may be predominantly trimers and tetramersof the starting olefins, with minor amounts of the higher oligomers,having a viscosity range of about 1.5 to 12 cSt. PAO base stocks andbase oils may be used in formulated lubricant composition or functionalfluids either individually or in any combination of two or more.

The PAO fluids may be conveniently made by the polymerization of analphaolefin in the presence of a polymerization catalyst such as theFriedel-Crafts catalysts including, for example, aluminum trichloride,boron trifluoride or complexes of boron trifluoride with water, alcoholssuch as ethanol, propanol or butanol, carboxylic acids or esters such asethyl acetate or ethyl propionate. For example the methods disclosed byU.S. Pat. No. 4,149,178 or U.S. Pat. No. 3,382,291 may be convenientlyused herein. Other descriptions of PAO synthesis are found in thefollowing U.S. Pat. Nos. 3,742,082; 3,769,363; 3,876,720; 4,239,930;4,367,352; 4,413,156; 4,434,408; 4,910,355; 4,956,122; and 5,068,487.The dimers of the C14 to C18 olefins are described in U.S. 4,218,330.All of the aforementioned patents are incorporated by reference hereinin their entirety.

Other types of synthetic PAO base stocks and base oils include highviscosity index lubricant fluids as described in U.S. Pat. Nos.4,827,064 and 4,827,073, which can be highly advantageously used incombination with the base stocks and base oils of this inventions, aswell as with in the formulated lubricant compositions or functionsfluids of this same invention. Other useful synthetic lubricating oilsmay also be utilized, for example, those described in the work“Synthetic Lubricants”, Gunderson and hart, Reinhold Publ. Corp., NewYork, 1962, which is incorporated in its entirety.

Other synthetic base stocks and base oils include hydrocarbon oils thatare derived from the oligomerization or polymerization of low-molecularweight compounds whose reactive group is not olefinic, into highermolecular weight compounds, which may be optionally reacted further orchemically modified in additional processes (e.g. isodewaxing,alkylation, esterification, hydroisomerization, dewaxing, etc.) to givea base oil of lubricating viscosity.

Hydrocarbyl aromatic base stocks and base oils are also widely used inlubrication oils and functional fluids. In alkylated aromatic stocks(hydrocarbyl aromatics, for example), the alkyl substituents aretypically alkyl groups of about 8 to 25 carbon atoms, usually from about10 to 18 carbon atoms and up to three such substituents may be present,as described for the alkyl benzenes in ACS Petroleum Chemistry Preprint1053-1058, “Poly n-Alkylbenzene Compounds: A Class of Thermally Stableand Wide Liquid Range Fluids”, Eapen et al, Phila. 1984. Tri-alkylbenzenes may be produced by the cyclodimerization of 1-alkynes of 8 to12 carbon atoms as described in U.S. Pat. No. 5,055,626. Otheralkylbenzenes are described in European Patent Application No. 168534and U.S. Pat. No. 4,658,072. Alkylbenzenes are used as lubricantbasestocks, especially for low-temperature applications (arctic vehicleservice and refrigeration oils) and in papermaking oils. They arecommercially available from producers of linear alkylbenzenes (LABs)such as Vista Chem. Co, Huntsman Chemical Co., Chevron Chemical Co., andNippon Oil Co. The linear alkylbenzenes typically have good low pourpoints and low temperature viscosities and VI values greater than 100together with good solvency for additives. Other alkylated aromaticswhich may be used when desirable are described, for example, in“Synthetic Lubricants and High Performance Functional Fluids”, Dressler,H., chap 5, (R. L. Shubkin (Ed.)), Marcel Dekker, N.Y. 1993. Aromaticbase stocks and base oils may include, for example, hydrocarbylalkylated derivatives of benzene, naphthalene, biphenyls, di-arylethers, di-aryl sulfides, di-aryl sulfones, di-aryl sulfoxides, di-arylmethanes or ethanes or propanes or higher homologues, mono- or di- ortri-aryl heterocyclic compounds containing one or more O, N, S, or P.

The hydrocarbyl aromatics that can be used can be any hydrocarbylmolecule that contains at least about 5% of its weight derived from anaromatic moiety such as a benzenoid moiety or naphthenoid moiety, ortheir derivatives. These hydrocarbyl aromatics include alkyl benzenes,alkyl naphthalenes, alkyl diphenyl oxides, alkyl naphthols, alkyldiphenyl sulfides, alkylated bis-phenol A, alkylated thiodiphenol, andthe like. The aromatic can be mono-alkylated, dialkylated,polyalkylated, and the like. The aromatic can be mono- orpoly-functionalized. The hydrocarbyl groups can also be comprised ofmixtures of alkyl groups, alkenyl groups, alkynyl, cycloalkyl groups,cycloalkenyl groups and other related hydrocarbyl groups. Thehydrocarbyl groups can range from about C6 up to about C60 with a rangeof about C8 to about C40 often being preferred. A mixture of hydrocarbylgroups is often preferred. The hydrocarbyl group can optionally containsulfur, oxygen, and/or nitrogen containing substituents. The aromaticgroup can also be derived from natural (petroleum) sources, provided atleast about 5% of the molecule is comprised of an above-type aromaticmoiety. Viscosities at 100 C of approximately 3 cSt to about 50 cSt arepreferred, with viscosities of approximately 3.4 cSt to about 20 cStoften being more preferred for the hydrocarbyl aromatic component. Inone embodiment, an alkyl naphthalene where the alkyl group is primarilycomprised of 1-hexadecene is used. Other alkylates of aromatics can beadvantageously used. Naphthalene, for example, can be alkylated witholefins such as octene, decene, dodecene, tetradecene or higher,mixtures of similar olefins, and the like. Useful concentrations ofhydrocarbyl aromatic in a lubricant oil composition can be about 2% toabout 25%, preferably about 4% to about 20%, and more preferably about4% to about 15%, depending on the application.

Other useful base stocks include wax isomerate base stocks and baseoils, comprising hydroisomerized waxy stocks (e.g. waxy stocks such asgas oils, slack waxes, fuels hydrocracker bottoms, etc.),hydroisomerized Fischer-Tropsch waxes, Gas-to-Liquids (GTL) base stocksand base oils, and other wax isomerate hydroisomerized base stocks andbase oils, or mixtures thereof. Fischer-Tropsch waxes, the high boilingpoint residues of Fischer-Tropsch synthesis, are highly paraffinichydrocarbons with very low sulfur content. The hydroprocessing used forthe production of such base stocks may use an amorphoushydrocracking/hydroisomerization catalyst, such as one of thespecialized lube hydrocracking (LHDC) catalysts or a crystallinehydrocracking/hydroisomerization catalyst, preferably a zeoliticcatalyst. For example, one useful catalyst is ZSM-48 as described inU.S. Pat. No. 5,075,269. Processes for makinghydrocracked/hydroisomerized distillates andhydrocracked/hydroisomerized waxes are described, for example, in U.S.Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as well as inBritish Patent Nos. 1,429,494; 1,350,257; 1,440,230 and 1,390,359.Particularly favorable processes are described in European PatentApplication Nos. 464546 and 464547. Processes using Fischer-Tropsch waxfeeds are described in U.S. Pat. Nos. 4,594,172 and 4,943,672.Gas-to-Liquids (GTL) base stocks and base oils, Fischer-Tropsch waxderived base stocks and base oils, and other wax isomeratehydroisomerized (wax isomerate) base stocks and base oils beadvantageously used in the instant invention, and may have usefulkinematic viscosities at 100 C of about 3 cSt to about 50 cSt,preferably about 3 cSt to about 30 cSt, more preferably about 3.5 cSt toabout 25 cSt, as exemplified by GTL4 with kinematic viscosity of about3.8 cSt at 100 C and a viscosity index of about 138. TheseGas-to-Liquids (GTL) base stocks and base oils, Fischer-Tropsch waxderived base stocks and base oils, and other wax isomeratehydroisomerized base stocks and base oils useful in the presentinvention have pour points of about −9° C. to −24° C., and under someconditions may have advantageous pour points of about −12° C. to −24° C.or even −15° C. to −22° C. Useful compositions of Gas-to-Liquids (GTL)base stocks and base oils, Fischer-Tropsch wax derived base stocks andbase oils, and wax isomerate hydroisomerized base stocks and base oilsare recited in U.S. Pat. Nos. 6,080,301; 6,090,989, and 6,165,949 forexample, and are incorporated herein in their entirety by reference.

Gas-to-Liquids (GTL) base stocks and base oils, Fischer-Tropsch waxderived base stocks and base oils, have a beneficial kinematic viscosityadvantage over conventional Group II and Group III base stocks and baseoils, which may be used as a co-base stock or co-base oil with theinstant invention. Gas-to-Liquids (GTL) base stocks and base oils canhave significantly higher kinematic viscosities, up to about 20-50 cStat 100 C, whereas by comparison commercial Group II base stocks and baseoils can have kinematic viscosities, up to about 15 cSt at 10° C., andcommercial Group III base stocks and base oils can have kinematicviscosities, up to about 10 cSt at 100 C. The higher kinematic viscosityrange of Gas-to-Liquids (GTL) base stocks and base oils, compared to themore limited kinematic viscosity range of Group II and Group III basestocks and base oils, in combination with the instant invention canprovide additional beneficial advantages in formulating lubricantcompositions. Also, the exceptionally low sulfur content ofGas-to-Liquids (GTL) base stocks and base oils, and other wax isomeratehydroisomerized base stocks and base oils, in combination with the lowsulfur content of suitable olefin oligomers and/or alkyl aromatics basestocks and base oils, and in combination with the instant invention canprovide additional advantages in lubricant compositions where very lowoverall sulfur content can beneficially impact lubricant performance.

Alkylene oxide polymers and interpolymers and their derivativescontaining modified terminal hydroxyl groups obtained by, for example,esterification or etherification are useful synthetic lubricating oils.By way of example, these oils may be obtained by polymerization ofethylene oxide or propylene oxide, the alkyl and aryl ethers of thesepolyoxyalkylene polymers (methyl-polyisopropylene glycol ether having anaverage molecular weight of about 1000, diphenyl ether of polyethyleneglycol having a molecular weight of about 500-1000, and the diethylether of polypropylene glycol having a molecular weight of about 1000 to1500, for example) or mono- and polycarboxylic esters thereof (theacidic acid esters, mixed C3-8 fatty acid esters, or the C130xo aciddiester of tetraethylene glycol, for example).

Esters comprise a useful base stock. Additive solvency and sealcompatibility characteristics may be secured by the use of esters suchas the esters of dibasic acids with monoalkanols and the polyol estersof monocarboxylic acids. Esters of the former type include, for example,the esters of dicarboxylic acids such as phthalic acid, succinic acid,alkyl succinic acid, alkenyl succinic acid, maleic acid, azelaic acid,suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic aciddimer, malonic acid, alkyl malonic acid, alkenyl malonic acid, etc.,with a variety of alcohols such as butyl alcohol, hexyl alcohol, dodecylalcohol, 2-ethylhexyl alcohol, etc. Specific examples of these types ofesters include dibutyl adipate, di(2-ethylhexyl)sebacate, di-n-hexylfumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate,dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, etc.

Particularly useful synthetic esters are those which are obtained byreacting one or more polyhydric alcohols, preferably the hinderedpolyols (such as the neopentyl polyols e.g. neopentyl glycol,trimethylol ethane, 2-methyl-2-propyl-1,3-propanediol, trimethylolpropane, pentaerythritol and dipentaerythritol) with alkanoic acidscontaining at least about 4 carbon atoms such as C5 to C30 acids (suchas saturated straight chain fatty acids including caprylic acid, capricacid, lauric acid, myristic acid, palmitic acid, stearic acid, arachicacid, and behenic acid, or the corresponding branched chain fatty acidsor unsaturated fatty acids such as oleic acid, or mixtures thereof).

Suitable synthetic ester components include esters of trimethylolpropane, trimethylol butane, trimethylol ethane, pentaerythritol and/ordipentaerythritol with one or more monocarboxylic acids containing fromabout 5 to about 10 carbon atoms. Such esters are widely availablecommercially, for example, the Mobil P-41 and P-51 esters (ExxonMobilChemical Company).

Other esters may included natural esters and their derivatives, fullyesterified or partially esterified, optionally with free hydroxyl orcarboxyl groups. Such ester may included glycerides, natural and/ormodified vegetable oils, derivatives of fatty acids or fatty alcohols.

Silicon-based oils are another class of useful synthetic lubricatingoils. These oils include polyalkyl-, polyaryl-, polyalkoxy-, andpolyaryloxy-siloxane oils and silicate oils. Examples of suitablesilicon-based oils include tetraethyl silicate, tetraisopropyl silicate,tetra-(2-ethylhexyl)silicate, tetra-(4-methylhexyl)silicate,tetra-(p-tert-butylphenyl)silicate,hexyl-(4-methyl-2-pentoxy)disiloxane, poly(methyl)siloxanes, andpoly-(methyl-2-methylphenyl)siloxanes.

Another class of synthetic lubricating oil is esters ofphosphorus-containing acids. These include, for example, tricresylphosphate, trioctyl phosphate, diethyl ester of decanephosphonic acid.

Another type of base stocks and base oils includes polymerictetrahydrofurans and the like, and their derivatives where reactivependant or end groups are partially or fully derivatized or capped withsuitable hydrocarbyl groups which may optionally contain O, N, or S.

The highly beneficial viscosity advantages of the base stocks and baseoils of this invention can be realized in combination with one or moreperformance additives, and with the desirable measured-to-theoreticalviscosity ratios at less than −25C, preferably at −30C or lower, beingrealized in the resulting formulated lubricant compositions orfunctional fluids. These lubricant compositions or functional fluidsalso have the unique and highly desirable characteristic of ameasured-to-theoretical viscosity ratio of 1.2 or lower, preferably 1.16or lower, and in many instances more preferably 1.12 or lower. Thus theeffect of the measured-to-theoretical viscosity feature of the basestocks and base oils of this invention is preserved even in the presenceof performance additives, leading to improved formulated lubricantcompositions or functional fluids comprising the base stocks and baseoils of this invention and one or more performance additives.

Performance Additives

The instant invention can be used with additional lubricant componentsin effective amounts in lubricant compositions, such as for examplepolar and/or non-polar lubricant base oils, and performance additivessuch as for example, but not limited to, metallic and ashless oxidationinhibitors, metallic and ashless dispersants, metallic and ashlessdetergents, corrosion and rust inhibitors, metal deactivators, anti-wearagents (metallic and non-metallic, low-ash, phosphorus-containing andnon-phosphorus, sulfur-containing and non-sulfur types), extremepressure additives (metallic and non-metallic, phosphorus-containing andnon-phosphorus, sulfur-containing and non-sulfur types), anti-seizureagents, pour point depressants, wax modifiers, viscosity indeximprovers, viscosity modifiers, seal compatibility agents, frictionmodifiers, lubricity agents, anti-staining agents, chromophoric agents,defoamants, demulsifiers, and others. For a review of many commonly usedadditives see Klamann in Lubricants and Related Products, Verlag Chemie,Deerfield Beach, Fla.; ISBN 0-89573-177-0, which also gives a gooddiscussion of a number of the lubricant additives discussed mentionedbelow. Reference is also made “Lubricant Additives” by M. W. Ranney,published by Noyes Data Corporation of Parkridge, N.J. (1973). Inparticular, the base oils of this invention can show significantperformance advantages with modern additives and/or additive systems,and additive packages that impart characteristics of low sulfur, lowphosphorus, and/or low ash to formulated lubricant compositions orfunctional fluids.

Anitwear and Extreme Pressure Additives

Additional antiwear additives may be used with the present invention.While there are many different types of antiwear additives, for severaldecades the principal antiwear additive for internal combustion enginecrankcase oils is a metal alkylthiophosphate and more particularly ametal dialkyldithiophosphate in which the primary metal constituent iszinc, or zinc dialkyldithiophosphate (ZDDP). ZDDP compounds generallyare of the formula Zn[SP(S)(OR¹)(OR²)]₂ where R¹ and R² are C₁-C₁₈ alkylgroups, preferably C₂-C₁₂ alkyl groups. These alkyl groups may bestraight chain or branched. For example, suitable alkyl groups includeisopropyl, 4-methyl-2-pentyl, and isooctyl. The ZDDP is typically usedin amounts of from about 0.4 wt % to about 1.4 wt. % of the total lubeoil composition, although more or less can often be used advantageously.

However, it is found that the phosphorus from these additives has adeleterious effect on the catalyst in catalytic converters and also onoxygen sensors in automobiles. One way to minimize this effect is toreplace some or all of the ZDDP with phosphorus-free antiwear additives.

A variety of non-phosphorus additives are also used as antiwearadditives. Sulfurized olefins are useful as antiwear and EP additives.Sulfur-containing olefins can be prepared by sulfurization or variousorganic materials including aliphatic, arylaliphatic or alicyclicolefinic hydrocarbons containing from about 3 to 30 carbon atoms,preferably 3-20 carbon atoms. The olefinic compounds contain at leastone non-aromatic double bond. Such compounds are defined by the formulaR³R⁴C═CR⁵R⁶ where each of R³-R⁶ are independently hydrogen or ahydrocarbon radical. Preferred hydrocarbon radicals are alkyl or alkenylradicals. Any two of R³-R⁶ may be connected so as to form a cyclic ring.Additional information concerning sulfurized olefins and theirpreparation can be found in U.S. Pat. No. 4,941,984, incorporated byreference herein in its entirety.

The use of polysulfides of thiophosphorus acids and thiophosphorus acidesters as lubricant additives is disclosed in U.S. Pat. Nos. 2,443,264;2,471,115; 2,526,497; and 2,591,577. Addition of phosphorothionyldisulfides as an antiwear, antioxidant, and EP additives is disclosed inU.S. Pat. No. 3,770,854. Use of alkylthiocarbamoyl compounds(bis(dibutyl)thiocarbamoyl, for example) in combination with amolybdenum compound (oxymolybdenum diisopropylphosphorodithioatesulfide, for example) and a phosphorus ester (dibutyl hydrogenphosphite, for example) as antiwear additives in lubricants is disclosedin U.S. Pat. No. 4,501,678. U.S. Pat. No. 4,758,362 discloses use of acarbamate additive to provide improved antiwear and extreme pressureproperties. The use of thiocarbamate as an antiwear additive isdisclosed in U.S. Pat. No. 5,693,598. Thiocarbamate/molybdenum complexessuch as moly-sulfur alkyl dithiocarbamate trimer complex (R═C₈-C₁₈alkyl) are also useful antiwear agents. Each of the above mentionedpatents is incorporated by reference herein in its entirety.

Esters of glycerol may be used as antiwear agents. For example, mono-,di, and tri-oleates, mono-palmitates and mono-myristates may be used.

ZDDP is combined with other compositions that provide antiwearproperties. U.S. Pat. No. 5,034,141 discloses that a combination of athiodixanthogen compound (octylthiodixanthogen, for example) and a metalthiophosphate (ZDDP, for example) can improve antiwear properties. U.S.Pat. No. 5,034,142 discloses that use of a metal alkyoxyalkylxanthate(nickel ethoxyethylxanthate, for example) and a dixanthogen(diethoxyethyl dixanthogen, for example) in combination with ZDDPimproves antiwear properties.

Antiwear additives may be used in an amount of about 0.01 to 6 weightpercent, preferably about 0.01 to 4 weight percent.

Viscosity Index Improvers

Viscosity index improvers (also known as VI improvers, viscositymodifiers, or viscosity improvers) provide lubricants with high- andlow-temperature operability. These additives impart shear stability atelevated temperatures and acceptable viscosity at low temperatures.

Suitable viscosity index improvers include both low molecular weight andhigh molecular weight hydrocarbons, polyesters and viscosity indeximprover dispersants that function as both a viscosity index improverand a dispersant. Typical molecular weights of these polymers arebetween about 10,000 to 1,000,000, more typically about 20,000 to500,00, and even more typically between about 50,000 and 200,000.

Examples of suitable viscosity index improvers are polymers andcopolymers of methacrylate, butadiene, olefins, or alkylated styrenes.Polyisobutylene is a commonly used viscosity index improver. Anothersuitable viscosity index improver is polymethacrylate (copolymers ofvarious chain length alkyl methacrylates, for example), someformulations of which also serve as pour point depressants. Othersuitable viscosity index improvers include copolymers of ethylene andpropylene, hydrogenated block copolymers of styrene and isoprene, andpolyacrylates (copolymers of various chain length acrylates, forexample). Specific examples include styrene-isoprene orstyrene-butadiene based polymers of about 50,000 to 200,000 molecularweight.

Viscosity index improvers may be used in an amount of about 0.01 to 15weight percent, preferably about 0.01 to 10 weight percent, and in someinstances, more preferably about 0.01 to 5 weight percent.

Antioxidants

Antioxidants retard the oxidative degradation of base oils duringservice. Such degradation may result in deposits on metal surfaces, thepresence of sludge, or a viscosity increase in the lubricant. Oneskilled in the art knows a wide variety of oxidation inhibitors that areuseful in lubricating oil compositions. See, Klamann in Lubricants andRelated Products, op cite, and U.S. Pat. Nos. 4,798,684 and 5,084,197,for example, the disclosures of which are incorporated by referenceherein in their entirety. Useful antioxidants include hindered phenols.These phenolic antioxidants may be ashless (metal-free) phenoliccompounds or neutral or basic metal salts of certain phenolic compounds.Typical phenolic antioxidant compounds are the hindered phenolics whichare the ones which contain a sterically hindered hydroxyl group, andthese include those derivatives of dihydroxy aryl compounds in which thehydroxyl groups are in the o- or p-position to each other. Typicalphenolic antioxidants include the hindered phenols substituted with C₆+alkyl groups and the alkylene coupled derivatives of these hinderedphenols. Examples of phenolic materials of this type 2-t-butyl-4-heptylphenol; 2-t-butyl-4-octyl phenol; 2-t-butyl-4-dodecyl phenol;2,6-di-t-butyl-4-heptyl phenol; 2,6-di-t-butyl-4-dodecyl phenol;2-methyl-6-t-butyl-4-heptyl phenol; and 2-methyl-6-t-butyl-4-dodecylphenol. Other useful hindered mono-phenolic antioxidants may include forexample hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.Bis-phenolic antioxidants may also be advantageously used in combinationwith the instant invention. Examples of ortho coupled phenols include:2,2′-bis(6-t-butyl-4-heptyl phenol); 2,2′-bis(6-t-butyl-4-octyl phenol);and 2,2′-bis(6-t-butyl-4-dodecyl phenol). Para coupled bis phenolsinclude for example 4,4′-bis(2,6-di-t-butyl phenol) and4,4′-methylene-bis(2,6-di-t-butyl phenol).

Non-phenolic oxidation inhibitors which may be used include aromaticamine antioxidants and these may be used either as such or incombination with phenolics. Typical examples of non-phenolicantioxidants include: alkylated and non-alkylated aromatic amines suchas aromatic monoamines of the formula R⁸R⁹R¹⁰N where R⁸ is an aliphatic,aromatic or substituted aromatic group, R⁹ is an aromatic or asubstituted aromatic group, and R¹⁰ is H, alkyl, aryl or R¹¹S(O)_(x)R¹²where R¹¹ is an alkylene, alkenylene, or aralkylene group, R¹² is ahigher alkyl group, or an alkenyl, aryl, or alkaryl group, and x is 0, 1or 2. The aliphatic group R⁸ may contain from 1 to about 20 carbonatoms, and preferably contains from 6 to 12 carbon atoms. The aliphaticgroup is a saturated aliphatic group. Preferably, both R⁸ and R⁹ arearomatic or substituted aromatic groups, and the aromatic group may be afused ring aromatic group such as naphthyl. Aromatic groups R⁸ and R⁹may be joined together with other groups such as S.

Typical aromatic amines antioxidants have alkyl substituent groups of atleast about 6 carbon atoms. Examples of aliphatic groups include hexyl,heptyl, octyl, nonyl, and decyl. Generally, the aliphatic groups willnot contain more than about 14 carbon atoms. The general types of amineantioxidants useful in the present compositions include diphenylamines,phenyl naphthylamines, phenothiazines, imidodibenzyls and diphenylphenylene diamines. Mixtures of two or more aromatic amines are alsouseful. Polymeric amine antioxidants can also be used. Particularexamples of aromatic amine antioxidants useful in the present inventioninclude: p,p′-dioctyldiphenylamine; t-octylphenyl-alpha-naphthylamine;phenyl-alphanaphthylamine; and p-octylphenyl-alpha-naphthylamine.

Sulfurized alkyl phenols and alkali or alkaline earth metal saltsthereof also are useful antioxidants. Low sulfur peroxide decomposersare useful as antioxidants.

Another class of antioxidant used in lubricating oil compositions isoil-soluble copper compounds. Any oil-soluble suitable copper compoundmay be blended into the lubricating oil. Examples of suitable copperantioxidants include copper dihydrocarbyl thio or dithio-phosphates andcopper salts of carboxylic acid (naturally occurring or synthetic).Other suitable copper salts include copper dithiacarbamates,sulphonates, phenates, and acetylacetonates. Basic, neutral, or acidiccopper Cu(I) and or Cu(II) salts derived from alkenyl succinic acids oranhydrides are know to be particularly useful.

Preferred antioxidants include hindered phenols, arylamines, low sulfurperoxide decomposers and other related components. These antioxidantsmay be used individually by type or in combination with one another.Such additives may be used in an amount of about 0.01 to 5 weightpercent, preferably about 0.01 to 2 weight percent.

Detergents

Detergents are commonly used in lubricating compositions. A typicaldetergent is an anionic material that contains a long chain oleophillicportion of the molecule and a smaller anionic or oleophobic portion ofthe molecule. The anionic portion of the detergent is typically derivedfrom an organic acid such as a sulfur acid, carboxylic acid, phosphorusacid, phenol, or mixtures thereof. The counter ion is typically analkaline earth or alkali metal.

Salts that contain a substantially stoichiometric amount of the metalare described as neutral salts and have a total base number (TBN, asmeasured by ASTM D2896) of from 0 to 80. Many compositions areoverbased, containing large amounts of a metal base that is achieved byreacting an excess of a metal compound (a metal hydroxide or oxide, forexample) with an acidic gas (such as carbon dioxide). Useful detergentscan be neutral, mildly overbased, or highly overbased.

It is desirable for at least some detergent to be overbased. Overbaseddetergents help neutralize acidic impurities produced by the combustionprocess and become entrapped in the oil. Typically, the overbasedmaterial has a ratio of metallic ion to anionic portion of the detergentof about 1.05:1 to 50:1 on an equivalent basis. More preferably, theratio is from about 4:1 to about 25:1. The resulting detergent is anoverbased detergent that will typically have a TBN of about 150 orhigher, often about 250 to 450 or more. Preferably, the overbasingcation is sodium, calcium, or magnesium. A mixture of detergents ofdiffering TBN can be used in the present invention. Preferred detergentsinclude the alkali or alkaline earth metal salts of sulfates, phenates,carboxylates, phosphates, and salicylates.

Sulfonates may be prepared from sulfonic acids that are typicallyobtained by sulfonation of alkyl substituted aromatic hydrocarbons.Hydrocarbon examples include those obtained by alkylating benzene,toluene, xylene, naphthalene, biphenyl and their halogenated derivatives(chlorobenzene, chlorotoluene, and chloronaphthalene, for example). Thealkylating agents typically have about 3 to 70 carbon atoms. The alkarylsulfonates typically contain about 9 to about 80 carbon or more carbonatoms, more typically from about 16 to 60 carbon atoms.

Klamann in Lubricants and Related Products, op cit discloses a number ofoverbased metal salts of various sulfonic acids which are useful asdetergents and dispersants in lubricants. The book entitled “LubricantAdditives”, C. V. Smallheer and R. K. Smith, published by theLezius-Hiles Co. of Cleveland, Ohio (1967), similarly discloses a numberof overbased sulfonates which are useful as dispersants/detergents.

Alkaline earth phenates are another useful class of detergent. Thesedetergents can be made by reacting alkaline earth metal hydroxide oroxide (CaO, Ca(OH)₂, BaO, Ba(OH)₂, MgO, Mg(OH)₂, for example) with analkyl phenol or sulfurized alkylphenol. Useful alkyl groups includestraight chain or branched C₁-C₃₀ alkyl groups, preferably, C₄-C₂₀.Examples of suitable phenols include isobutylphenol, 2-ethylhexylphenol,nonylphenol, 1-ethyldecylphenol, and the like. It should be noted thatstarting alkylphenols may contain more than one alkyl substituent thatare each independently straight chain or branched. When a non-sulfurizedalkylphenol is used, the sulfurized product may be obtained by methodswell known in the art. These methods include heating a mixture ofalkylphenol and sulfurizing agent (including elemental sulfur, sulfurhalides such as sulfur dichloride, and the like) and then reacting thesulfurized phenol with an alkaline earth metal base.

Metal salts of carboxylic acids are also useful as detergents. Thesecarboxylic acid detergents may be prepared by reacting a basic metalcompound with at least one carboxylic acid and removing free water fromthe reaction product. These compounds may be overbased to produce thedesired TBN level. Detergents made from salicylic acid are one preferredclass of detergents derived from carboxylic acids. Useful salicylatesinclude long chain alkyl salicylates, where alkyl groups have 1 to about30 carbon atoms, with 1 to 4 alkyl group per benzenoid nucleus, and withthe metal of the compound including alkaline earth metal. Preferred Rgroups are alkyl chains of at least about Cl₁, preferably C₁₃ orgreater. R may be optionally substituted with substituents that do notinterfere with the detergent's function. M is preferably, calcium,magnesium, or barium. More preferably, M is calcium.

Hydrocarbyl-substituted salicylic acids may be prepared from phenols bythe Kolbe reaction. See U.S. Pat. No. 3,595,791 for additionalinformation on synthesis of these compounds. The metal salts of thehydrocarbyl-substituted salicylic acids may be prepared by doubledecomposition of a metal salt in a polar solvent such as water oralcohol. Alkaline earth metal phosphates are also used as detergents.

Detergents may be simple detergents or what is known as hybrid orcomplex detergents. The latter detergents can provide the properties oftwo detergents without the need to blend separate materials. See U.S.Pat. No. 6,034,039 for example.

Preferred detergents include calcium phenates, calcium sulfonates,calcium salicylates, magnesium phenates, magnesium sulfonates, magnesiumsalicylates and other related components (including borated detergents).Typically, the total detergent concentration is about 0.01 to about 6weight percent, preferably, about 0.1 to 4 weight percent.

In addition, non-ionic detergents may be preferably used in lubricatingcompositions. Such non-ionic detergents may be ashless or low-ashcompounds, and may include discrete molecular compounds, as well asoligomeric and/or polymeric compounds.

Dispersants

During engine operation, oil insoluble oxidation byproducts areproduced. Dispersants help keep these byproducts in solution, thusdiminishing their deposit on metal surfaces. Dispersants may be ashlessor ash-forming in nature. Preferably, the dispersant is ashless. Socalled ashless dispersants are organic materials that form substantiallyno ash upon combustion. For example, non-metal-containing or boratedmetal-free dispersants are considered ashless. In contrast,metal-containing detergents discussed above form ash upon combustion.

Suitable dispersants typically contain a polar group attached to arelatively high molecular weight hydrocarbon chain. The polar grouptypically contains at least one element of nitrogen, oxygen, orphosphorous. Typical hydrocarbon chains contain about 50 to 400 carbonatoms.

Dispersants include phenates, sulfonates, sulfurized phenates,salicylates, naphthenates, stearates, carbamates, thiocarbamates, andphosphorus derivatives. A particularly useful class of dispersants arealkenylsuccinic derivatives, typically produced by the reaction of along chain substituted alkenyl succinic compound, usually a substitutedsuccinic anhydride, with a polyhydroxy or polyamino compound. The longchain group constituting the oleophilic portion of the molecule whichconfers solubility in the oil, is normally a polyisobutylene group. Manyexamples of this type of dispersant are well known. Exemplary U.S.Patents describing such dispersants include U.S. Pat. Nos. 3,172,892;3,2145,707; 3,219,666; 3,316,177; 3,341,542; 3,444,170; 3,454,607;3,541,012; 3,630,904; 3,632,511; 3,787,374 and 4,234,435. Other types ofdispersants are described in U.S. Pat. Nos. 3,036,003; 3,200,107;3,254,025; 3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,413,347;3,697,574; 3,725,277; 3,725,480; 3,726,882; 4,454,059; 3,329,658;3,449,250; 3,519,565; 3,666,730; 3,687,849; 3,702,300; 4,100,082;5,705,458. A further description of dispersants is also found inEuropean Patent Application No. 471 071. Each of the above noted patentsand patent applications is incorporated herein by reference in itsentirety.

Hydrocarbyl-substituted succinic acid compounds are well knowndispersants. In particular, succinimide, succinate esters, or succinateester amides prepared by the reaction of hydrocarbon-substitutedsuccinic acid preferably having at least 50 carbon atoms in thehydrocarbon substituent, with at least one equivalent of an alkyleneamine, are particularly useful.

Succinimides are formed by the condensation reaction between alkenylsuccinic anhydrides and amines. Molar ratios can vary depending on thepolyamine. For example, the molar ratio of alkenyl succinic anhydride toTEPA can vary from about 1:1 to about 5:1. Representative examples areshown in U.S. Pat. Nos. 3,087,936; 3,172,892; 3,219,666; 3,272,746;3,322,670; 3,652,616; 3,948,800; and Canada Pat. No. 1,094,044, each ofwhich is incorporated by reference herein in its entirety.

Succinate esters are formed by the condensation reaction between alkenylsuccinic anhydrides and alcohols or polyols. Molar ratios can varydepending on the alcohol or polyol used. For example, the condensationproduct of an alkenyl succinic anhydride and pentaerythritol is a usefuldispersant.

Succinate ester amides are formed by condensation reaction betweenalkenyl succinic anhydrides and alkanol amines. For example, suitablealkanol amines include ethoxylated polyalkylpolyamines, propoxylatedpolyalkylpolyamines and polyalkenylpolyamines such as polyethylenepolyamines. One example is propoxylated hexamethylenediamine.Representative examples are shown in U.S. Pat. No. 4,426,305,incorporated by reference herein in its entirety.

The molecular weight of the alkenyl succinic anhydrides used in thepreceding paragraphs will range between about 800 and 2,500. The aboveproducts can be post-reacted with various reagents such as sulfur,oxygen, formaldehyde, carboxylic acids such as oleic acid, and boroncompounds such as borate esters or highly borated dispersants. Thedispersants can be borated with from about 0.1 to about 5 moles of boronper mole of dispersant reaction product, including those derived frommono-succinimides, bis-succinimides (also known as disuccinimides), andmixtures thereof.

Mannich base dispersants are made from the reaction of alkylphenols,formaldehyde, and amines. See U.S. Pat. No. 4,767,551, incorporated byreference herein in its entirety. Process aids and catalysts, such asoleic acid and sulfonic acids, can also be part of the reaction mixture.Molecular weights of the alkylphenols range from 800 to 2,500.Representative examples are shown in U.S. Pat. Nos. 3,697,574;3,703,536; 3,704,308; 3,751,365; 3,756,953; 3,798,165; and 3,803,039,which are incorporated herein by reference in its entirety.

Typical high molecular weight aliphatic acid modified Mannichcondensation products useful in this invention can be prepared from highmolecular weight alkyl-substituted hydroxyaromatics or HN(R)₂group-containing reactants.

Examples of high molecular weight alkyl-substituted hydroxyaromaticcompounds are polypropylphenol, polybutylphenol, and otherpolyalkylphenols. These polyalkylphenols can be obtained by thealkylation, in the presence of an alkylating catalyst, such as BF3, ofphenol with high molecular weight polypropylene, polybutylene, and otherpolyalkylene compounds to give alkyl substituents on the benzene ring ofphenol having an average 600-100,000 molecular weight.

Examples of HN(R)2 group-containing reactants are alkylene polyamines,principally polyethylene polyamines. Other representative organiccompounds containing at least one HN(R)2 group suitable for use in thepreparation of Mannich condensation products are well known and includemono- and di-amino alkanes and their substituted analogs, e.g.,ethylamine and diethanol amine; aromatic diamines, e.g., phenylenediamine, diamino naphthalenes; heterocyclic amines, e.g., morpholine,pyrrole, pyrrolidine, imidazole, imidazolidine, and piperidine; melamineand their substituted analogs.

Examples of alkylene polyamide reactants include ethylenediamine,diethylene triamine, triethylene tetraamine, tetraethylene pentaamine,pentaethylene hexamine, hexaethylene heptaamine, heptaethyleneoctaamine, octaethylene nonaamine, nonaethylene decamine, decaethyleneundecamine, and mixtures of such amines. Some preferred compositionscorrespond to formula H2N-(Z-NH—)nH, where Z is a divalent ethylene andn is 1 to 10 of the foregoing formula. Corresponding propylenepolyamines such as propylene diamine and di-, tri-, tetra-,pentapropylene tri-, tetra-, penta- and hexaamines are also suitablereactants. Alkylene polyamines usually are obtained by the reaction ofammonia and dihalo alkanes, such as dichloro alkanes. Thus, the alkylenepolyamines obtained from the reaction of 2 to 11 moles of ammonia with 1to 10 moles of dichloro alkanes having 2 to 6 carbon atoms and thechlorines on different carbons are suitable alkylene polyaminereactants.

Aldehyde reactants useful in the preparation of the high molecularproducts useful in this invention include aliphatic aldehydes such asformaldehyde (such as paraformaldehyde and formalin), acetaldehyde andaldol (b-hydroxybutyraldehyde, for example). Formaldehyde or aformaldehyde-yielding reactant is preferred.

Hydrocarbyl substituted amine ashless dispersant additives are wellknown to those skilled in the art. See, for example, U.S. Pat. Nos.3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209, and 5,084,197,each of which is incorporated by reference in its entirety.

Preferred dispersants include borated and non-borated succinimides,including those derivatives from mono-succinimides, bis-succinimides,and/or mixtures of mono- and bis-succinimides, wherein the hydrocarbylsuccinimide is derived from a hydrocarbylene group such aspolyisobutylene having a Mn of from about 500 to about 5000 or a mixtureof such hydrocarbylene groups. Other preferred dispersants includesuccinic acid-esters and amides, alkylphenol-polyamine coupled Mannichadducts, their capped derivatives, and other related components. Suchadditives may be used in an amount of about 0.1 to 20 weight percent,preferably about 0.1 to 8 weight percent.

Other dispersants may include oxygen-containing compounds, such aspolyether compounds, polycarbonate compounds, and/or polycarbonylcompounds, as oligomers or polymers, ranging from low molecular weightto high molecular weight.

Friction Modifiers

A friction modifier is any material or materials that can alter thecoefficient of friction of any lubricant or fluid containing suchmaterial(s). Friction modifiers, also known as friction reducers, orlubricity agents or oiliness agents, and other such agents that changethe coefficient of friction of lubricant base oils, formulated lubricantcompositions, or functional fluids, may be effectively used incombination with the base oils or lubricant compositions of the presentinvention if desired. Friction modifiers that lower the coefficient offriction are particularly advantageous in combination with the base oilsand lube compositions of this invention. Friction modifiers may includemetal-containing compounds or materials as well as ashless compounds ormaterials, or mixtures thereof. Metal-containing friction modifiers mayinclude metal salts or metal-ligand complexes where the metals mayinclude alkali, alkaline earth, or transition group metals. Suchmetal-containing friction modifiers may also have low-ashcharacteristics. Transition metals may include Mo, Sb, Sn, Fe, Cu, Zn,and others. Ligands may include hydrocarbyl derivative of alcohols,polyols, glycerols, partial ester glycerols, thiols, carboxylates,carbamates, thiocarbamates, dithiocarbamates, phosphates,thiophosphates, dithiophosphates, amides, imides, amines, thiazoles,thiadiazoles, dithiazoles, diazoles, triazoles, and other polarmolecular functional groups containing effective amounts of O, N, S, orP, individually or in combination. In particular, Mo-containingcompounds can be particularly effective such as for exampleMo-dithiocarbamates, Mo(DTC), Mo-dithiophosphates, Mo(DTP), Mo-amines,Mo (Am), Mo-alcoholates, Mo-alcohol-amides, etc.

Ashless friction modifiers may have also include lubricant materialsthat contain effective amounts of polar groups, for examplehydroxyl-containing hydrocaryl base oils, glycerides, partialglycerides, glyceride derivatives, and the like. Polar groups infriction modifiers may include hyrdocarbyl groups containing effectiveamounts of O, N, S, or P, individually or in combination. Other frictionmodifiers that may be particularly effective include, for example, salts(both ash-containing and ashless derivatives) of fatty acids, fattyalcohols, fatty amides, fatty esters, hydroxyl-containing carboxylates,and comparable synthetic long-chain hydrocarbyl acids, alcohols, amides,esters, hydroxy carboxylates, and the like. In some instances fattyorganic acids, fatty amines, and sulfurized fatty acids may be used assuitable friction modifiers.

Useful concentrations of friction modifiers may range from about 0.01 wt% to 10-15 wt % or more, often with a preferred range of about 0.1 wt %to 5 wt %. Concentrations of molybdenum containing materials are oftendescribed in terms of Mo metal concentration. Advantageousconcentrations of Mo may range from about 10 ppm to 3000 ppm or more,and often with a preferred range of about 20-2000 ppm, and in someinstances a more preferred range of about 30-1000 ppm. Frictionmodifiers of all types may be used alone or in mixtures with thematerials of this invention. Often mixtures of two or more frictionmodifiers, or mixtures of friction modifiers(s) with alternate surfaceactive material(s), are also desirable.

Pour Point Depressants

Conventional pour point depressants (also known as lube oil flowimprovers) may be added to the compositions of the present invention ifdesired. These pour point depressant may be added to lubricatingcompositions of the present invention to lower the minimum temperatureat which the fluid will flow or can be poured. Examples of suitable pourpoint depressants include polymethacrylates, polyacrylates,polyarylamides, condensation products of haloparaffin waxes and aromaticcompounds, vinyl carboxylate polymers, and terpolymers ofdialkylfumarates, vinyl esters of fatty acids and allyl vinyl ethers.U.S. Pat. Nos. 1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479;2,666,746; 2,721,877; 2,721,878; and 3,250,715 describe useful pourpoint depressants and/or the preparation thereof. Each of thesereferences is incorporated herein in its entirety. Such additives may beused in an amount of about 0.01 to 5 weight percent, preferably about0.01 to 1.5 weight percent.

Corrosion Inhibitors

Corrosion inhibitors are used to reduce the degradation of metallicparts that are in contact with the lubricating oil composition. Suitablecorrosion inhibitors include thiadizoles. See, for example, U.S. Pat.Nos. 2,719,125; 2,719,126; and 3,087,932, which are incorporated hereinby reference in their entirety. Such additives may be used in an amountof about 0.01 to 5 weight percent, preferably about 0.01 to 1.5 weightpercent.

Seal Compatibility Additives

Seal compatibility agents help to swell elastomeric seals by causing achemical reaction in the fluid or physical change in the elastomer.Suitable seal compatibility agents for lubricating oils include organicphosphates, aromatic esters, aromatic hydrocarbons, esters (butylbenzylphthalate, for example), and polybutenyl succinic anhydride. Additivesof this type are commercially available. Such additives may be used inan amount of about 0.01 to 3 weight percent, preferably about 0.01 to 2weight percent.

Anti-Foam Agents

Anti-foam agents may advantageously be added to lubricant compositions.These agents retard the formation of stable foams. Silicones and organicpolymers are typical anti-foam agents. For example, polysiloxanes, suchas silicon oil or polydimethyl siloxane, provide antifoam properties.Anti-foam agents are commercially available and may be used inconventional minor amounts along with other additives such asdemulsifiers; usually the amount of these additives combined is lessthan 1 percent and often less than 0.1 percent.

Inhibitors and Antirust Additives

Antirust additives (or corrosion inhibitors) are additives that protectlubricated metal surfaces against chemical attack by water or othercontaminants. A wide variety of these are commercially available; theyare referred to also in Klamann, op. cit.

One type of antirust additive is a polar compound that wets the metalsurface preferentially, protecting it with a film of oil. Another typeof antirust additive absorbs water by incorporating it in a water-in-oilemulsion so that only the oil touches the metal surface. Yet anothertype of antirust additive chemically adheres to the metal to produce anon-reactive surface. Examples of suitable additives include zincdithiophosphates, metal phenolates, basic metal sulfonates, fatty acidsand amines. Such additives may be used in an amount of about 0.01 to 5weight percent, preferably about 0.01 to 1.5 weight percent. Additionaltypes of additives may be further incorporated into lubricantcompositions or functional fluids of this invention, and may include oneor more additives such as, for example, demulsifiers, solubilizers,fluidity agents, coloring agents, chromophoric agents, and the like, asrequired. Further, each additive type may include individual additivesor mixtures of additive.

Note that many additives, additive concentrates, and additive packagesthat are purchased from manufacturers may incorporate a certain amountof base oil solvent, or diluent, in the formulation. In practicalapplications, however, additive components, additive concentrates, andadditive packages are used as purchased from manufactures, and mayinclude certain amounts of base oil solvent or diluent. The additive andformulation components as recited in the Examples and ComparativeExamples below are used “as is” from their manufacturers or suppliers,unless specifically noted otherwise.

EXAMPLES Example 1

By controlling other non-inventive process parameters well known tothose skilled in the art, the base stocks incorporated into thefunctional fluids of this inventions as described herein can be madeover a range of low to high viscosity oils as is typical in the industrythus allowing for blending of base stocks with a final viscosity betweenthose two end points. In this first example, the base stocks weremanufactured using the inventive method to a higher viscosity level of6.6 cSt and a lower viscosity level of 4.0 cSt. As may be seen in table3, the Inventive Oil A (isomerized slack wax) was then blended to twoviscometric targets: 4.0 cSt and 5.7 cSt. Similarly, the Inventive Oil Bfor this example was made from a Fischer-Tropsch wax, blended to finalviscosity targets of 4.0 cSt and 6.3 cSt. The Comparitive Base Oils forexample 1 are commercially available base stocks blended to viscometrictargets of 4 cSt, 5 cSt and 8 cSt.

Viscometric properties of Inventive base oils A and B and theComparative Base Oil 1 at comparable viscosity indices are shown below(Table 3). The Kinematic Viscosities were measured by ASTM method D445.The measured CCS viscosity were found by using ASTM method D5293. TheTheoretical Viscosity were calculated per the Walther/MacCoull Equationas found in ASTM D341 (Appendix 1). For this example, and as shown inFIG. 2, the linear Theoretical Viscosity line for each oil of interestwas determined from the kinematic viscosities taken at 40 C and 100 C.

Table 3 shows unexpectedly that the ratio between measured andtheoretical viscosity (i.e. ratio=measured/theoretical) at −30 C orbelow is less than 1.2 for the Inventive Base Oils, but is higher than1.2 for the Comparative Base Oils at the same temperatures. It hassimilarly being observed that the inventive base stocks have a muchlower scanning Brookfield viscosity (ASTM D5133) values at lowtemperature (below −20C). Scanning Brookfield viscosity measurements areperformed at much lower shear rates, and slower cooling rates than theD5293 CCS technique. In the particular example illustrate in table 4,the inventive base stocks ratios of (measured/theoretically predicted)viscosity ranges between 2.5 (@−20C) and 7 (@−35C), while the comparablecommercially available base stock, with similar viscosity and VI, has aratio ranging between 11 (@−20C), and 63 (@−25C), and its viscosity isto high to be measured below −25C. TABLE 3 Base Stocks and PropertiesComparative Base Oil Inventive Base Oil Comp. Oil Comp. Oil Comp. OilOil A Oil A Oil B Oil B 1 1 1 4 cSt 5.7 cSt 4 cSt 6.3 cSt 4 cSt 5 cSt 8cSt Viscosity Index 142 150 143 153 142 146 146 Kinematic Viscosity,ASTM D445 at 100 C., cSt 4 5.7 3.8 6.30 4.0 5.1 8.0 at 40 C., cSt 16.828.4 15.3 31.8 16.5 24.1 46.3 CCS Viscosity (Measured), ASTM D5293 at−30 C., cP TLTM 2506 680 2630 1160 2270 8000 at −35 C., cP 1354 44991140 4670 2440 4620 THTM Theoretical Viscosity (Walther/MacCoull Eq.) at−30 C., cP 894 2439 722 2806 866 1877 6056 at −35 C., cP 1515 4364 12065019 1466 3329 11340 Viscosity Ratio, measured/theoretical at −30 C., cP— 1.03 0.94 0.94 1.34 1.21 1.32 at −35 C., cP 0.89 1.03 0.94 0.93 1.661.39 —(TLTM = too low to measure)(THTM = too high to measure)

Example 2

For example 2, five blended functional fluids were created. Blend 1, thecomparative example, is a functional fluid made from a commerciallyavailable Group II base stock with the same target viscosity level asthe inventive examples (see table 4). Blends 2 and 3 and Blends 6 and 7are functional fluids incorporating Inventive Base Stock A from Example1, specifically the 4 cSt viscosity target specification. Blends 4 and 5are functional fluids incorporating Inventive Base Stock B from Example1, specifically the 4 cSt viscosity target.

The properties of Comparative Blend 1 and Inventive Blends 2-7 atcomparable viscosity indices are shown below in Table 4. The KinematicViscosities were measured by ASTM method D445. Brookfield viscositieswere measured by ASTM method D2983. Pour point was measured by ASTMD5950. Blend 1 is the average results of Blends 1A and 1B seen in Table5. TABLE 4 Blend 1 Blend 2 Blend 3 Blend 4 Blend 5 Blend 6 Blend 7Component, vol % Comparative base stock 88.621 43.511 — 44.011 — 70.39556.893 Inventive base stock A — 44.894 88.286 — — 18.161 31.608Inventive base stock B — — — 43.939 87.657 — — Additives 11.379 11.59511.714 12.050 12.343 11.144 11.499 Finished ATF Viscosity @ 100° C., cSt7.614 7.657 7.677 7.606 7.482 7.618 7.613 Viscosity @ 40° C., cSt 35.6033.43 31.63 32.53 29.60 34.57 33.97 Viscosity Index 191 210 227 215 237199 203 Brookfield @ −40° C., cP 19,278 9,150 8,950 8,733 7,138 1298710328 Base Oil (49.2/50.8) (79.5/20.5) (64.3/35.7) Comparative/Inventive100/0 50/50 0/100 50/50 0/100 80/20 65/35 base stock ratio, vol %Viscosity @ 100° C., cSt 3.906 3.957 4.007 3.842 3.780 3.880 3.860 PourPoint, ° C. −20 −20 −20 −19.5 −19 −20 −20 Cloud Point, ° C. −16.2 —−15.1 — −7.8 — —

The unexpected finding of the instant invention is that the Brookfieldviscosity of the functional fluids of the present invention measured at−40° C. is dramatically lower than that found using a comparativeHydrocracked (HC) Group II base stock. The observed phenomenon occurredeven though the pour point and cloud point of the Inventive base stockswere equivalent to the Hydrocracked (HC) Group II base stock. Moresurprisingly, functional fluids of the current invention made with up to50 vol % of the Group II base stocks still exhibited the exceptionalBrookfield viscosities at −40C. The inventors have found that thesesurprising results appear at blends of 65 vol % and even up to 80 vol %Group II base stocks.

Example 3

In an effort to recreate the results of the current invention which usesthe catalytic dewaxing, by employing standard solvent dewaxing base oilextraction techniques, a third experiment was performed. Thecommercially available Group II base stock of Example 2 was subjected to18 modifications commonly used to improve the low temperature propertiesof the base stock. These modifications were incorporated into functionalfluids and the Brookfield Viscosity of each functional fluid wasmeasured. The results are compared to the Brookfield viscosities of theInventive functional fluids from Example 2 (Blends 2-5) in Table 5.TABLE 5 Base Stock Blend Pour ATF Brookfield cP ATF Brookfield cP #Point ° C. (Comparative Base Oils) (Inventive Base Oils) 1A −20 19,0261B −20 19,530 1-1 −20 18,869 1-2 −23 15,950 1-3 −21 17,269 1-4 −1824,395 1-5 −15 26,869 1-6 −19 22,345 1-7 −14 26,669 1-8 −20 19,226 1-9−23 16,207 1-10 −21 18,906 1-11 −22 16,097 1-12 −20 23,395 1-13 −2417,246 1-14 −26 17,896 1-15 −19 17,596 1-16 −20 17,496 1-17 −20 17,9461-18 −23 15,547 2 −20 9,150 3 −20 8,950 4 −19.5 8,733 5 −19 7,138

Table 5 demonstrates that none of the modifications to the Group II baseoil extraction techniques produced Brookfield viscosities remotely closeto those of the functional fluids of the present invention. Theseresults are graphically represented in FIG. 3.

Example 4

To demonstrate that the advantages of the current invention occur overthe range of viscosity targets, Inventive base Oil A of Example 1 wasmixed to various viscosity targets. Likewise, the Comparative Base oilof Example 1 was blended to the same target viscosities. The CCSviscosities of each blend were measured.

As table 6 demonstrates, the viscosity-temperature performance for theComparative Base Oil and the Inventive Base Oil are also demonstrablydifferent over a range of base oil viscosity, as measured by kinematicviscosity at 100 C. At comparable kinematic viscosity at 100 C, it isevident that the Inventive Base Oil has superior (i.e. lower)low-temperature viscosity than that of comparative base oil 1, attemperatures such as, for example, −30C and −35C. TABLE 6 Base Oil CCSLow-Temperature Viscosity at Comparable Kinematic Viscosity andVolatility Inventive Base Oil A Comparative Base Oil 1 4-6.6 cStMixtures 4-8 cSt Mixtures CCS @ −30 CCS @ −35 CCS @ −30 CCS @ −35 KV @100 C., cSt C. CP C. cP C. cP C. CP 4.0 857 1445 1524 2798 4.6 1282 22142032 3713 6.0 2830 5120 3600 6700

Example 5

The beneficial property of inventive base stocks and base oils toadvantageously lower CCS viscosity for functional fluids blended withGroup I base stocks as well as those blended with Group II base stocks.For example 5, the Inventive Base Oil A of Example 1 blended to a targetof 5 cSt was then further blended into a Group I base stock. Thecommercially available Comparative Base Oil of Example 1 was alsoblended with a Group I base stock. Each blend received the same amountof a performance additive package and a standard viscosity modifiercommon to functional fluids commercially available. The results of theCCS viscosity test is presented in Table 7. TABLE 7 CCS Viscosity Changeand Formulated Functional Fluids Inventive Comparative Example Example 6CE. 6 Formulated Lubricant Composition (wt %) Inventive Base Oil A 50 (4& 6.6 cSt blend) Comparative Base Oil 1 50 (5 cSt) Group 1 Base Stock13.8 13.8 Performance Additive Package 2 23 23 Viscosity Modifier 1(SICP) 13.2 13.2 Properties Kinematic Viscosity @ 100 C., cSt 13.6213.65 CCS Viscosity @ −20 C., cP 2870 3200 CCS Viscosity @ −25 C., cP5130 6280

Table 7 demonstrates that there is a CCS viscosity benefit (i.e. lowerCCS viscosity) at −20C and at −25C for a formulation incorporating aGroup I base stock when blending with the Inventive base oil relative toa comparable formulation using Comparative Base Oil 1. Even moresurprisingly, the CCS viscosity benefit difference for formulatedlubricant based on Inventive base oil (Example 4) compared toComparative Base Oil 1 (Comparative Example 4) becomes greater as thetemperature decreases (Table 7).

1. A method for producing functional fluid containing a Group II orGroup III base stock and having a Brookfield Viscosity at −40° C. ofabout 15,000 cp or less comprising: (I) adding from about 50 vol % toabout 20 vol % of at least one first base stock having (a) a kinematicviscosity of 1.5 to about 8.5 mm²/sec at 100° C., (b) a viscosity indexof about 120 to about 160, (c) a pour point of about −9° C. to −24° C.,(d) a saturates content of about 92 to about 100 mass % made fromnatural mineral or synthetic waxy hydrocarbon feedstock which waxyfeedstocks have a wax content of at least about 50 wt % and which waxyfeedstocks are converted into said base stock by (i) hydrotreating thewaxy feedstock with a hydrotreating catalyst under effectivehydrotreating conditions such that less than 5 wt % of the feedstock isconverted to 343° C. (650° F.) minus products to produce a hydrotreatedfeedstock whose VI increase is less than 4 greater than the VI of thewaxy feedstock; (ii) stripping or distilling the hydrotreated feedstockto separate gaseous product form liquid product; (iii) hydrodewaxing theliquid product with a dewaxing catalyst under catalytically effectivehydrodewaxing conditions wherein the dewaxing catalyst contains at leastone Group 9 or Group 10 noble metal; (iv) optionally hydrofinishing theproduct from (iii) with a hydrofinishing catalyst under hydrofinishingconditions; (II) from about 50 vol % to 80 vol % of a hydrocracked GroupII or Group III or mixture thereof comprising one or more hydrocrackedbases stocks having: (a) a kinematic viscosity of about 1.5 to about 8.5mm²/sec at 100° C., (b) a viscosity index of about 90 or higher, (c) apour point of about −15° C. or less, (d) a saturates content of about 92to about 100 mass % said mixture of base stocks having: (a) a kinematicviscosity of about 3 mm²/sec to about 6.5 mm²/sec at 100° C., (b) aviscosity index of about 120 to about 150, (c) a pour point of about−15° C. or less; and (III) at least one performance additive; whereinsaid functional fluid has: (a) a kinematic viscosity of about 4.5 toabout 9.5 mm²/sec at 100° C., (b) a viscosity index of about 150 toabout 230, (c) a pour point of about −42° C. or less, and (d) aBrookfield viscosity of about 15,000 cP or less at −40° C.
 2. The methodof claim 1 wherein said functional fluid has a kinematic viscosity ofabout 5.5 to about 8.5 mm²/sec at 100° C.
 3. The method of claim 1wherein said functional fluid has a Brookfield viscosity of about 13,000cP or less at −40° C.
 4. The method of claim 1 wherein said functionalfluid has a Brookfield viscosity of about 10,000 cP or less at −40° C.5. The method of claim 1 wherein said first base stock incorporated intosaid functional fluid has a kinematic viscosity of about 2.0 to about6.0 mm²/sec at 100° C.
 6. The method of claim 1 wherein said first basestock incorporated into said functional fluid has a kinematic viscosityof about 3.0 to about 5.0 mm²/sec at 100° C.
 7. The method of claim 1wherein said first base stock incorporated into said functional fluidhas a viscosity index of about 130 to about
 150. 8. The method of claim1 wherein said first base stock incorporated into said functional fluidhas a pour point of about −12° C. to −24° C.
 9. The method of claim 1wherein said first base stock incorporated into said functional fluidhas a saturates content of about 96 to about 100 mass %.
 10. The methodof claim 1 wherein: (I) the at least one first base stock has (a) akinematic viscosity of 3.0 to about 5.0 mm²/sec at 100° C., (b) aviscosity index of about 130 to about 150, (c) a pour point of about−15° C. to −24° C., (d) a saturates content of about 96 to about 100mass %; and (II) the about 50 vol % to 80 vol %, of hydrocracked GroupII or Group III base stock or mixture thereof comprising one or morehydrocracked bases stocks has: (a) a kinematic viscosity of about 1.5 toabout 6.5 mm²/sec at 100° C., (b) a viscosity index of about 90 orhigher, (c) a pour point of about −15° C. or less, (d) a saturatescontent of about 92 to about 100 mass % wherein said mixture of basestocks has: (a) a kinematic viscosity of about 3.5 mm²/sec to about 5.5mm²/sec at 100° C., (b) a viscosity index of about 120 to about 150, (c)a pour point of about −15° C. or less; and wherein said functional fluidhas: (a) a kinematic viscosity of about 5.5 to about 8.5 mm²/sec at 100°C., (b) a viscosity index of about 150 to about 230, (c) a pour point ofabout −42° C. or less, and (d) a Brookfield viscosity of about 13,000 cPor less at −40° C.
 11. The method of claim 1 wherein the functionalfluid is an Automatic Transmission Fluid.
 12. The method of claim 1wherein said first base stock is a gas-to-liquid base stock.
 13. Themethod of claim 10 wherein the functional fluid is an AutomaticTransmission Fluid.
 14. The method of claim 10 wherein said first basestock is a gas-to-liquid base stock.
 15. The method of claim 11 whereinsaid first base stock is a gas-to-liquid base stock.
 16. The method ofclaim 1, 11, 12, 13, 14 or 15, wherein the hydrodewaxing of the liquidproduct with a dewaxing catalyst uses as the dewaxing catalyst at leastone of ZSM-48, ZSM-57, ZSM-23, ZSM-22, ZSM-35, ferrierite, ECR-42,ITQ-13, MCM-71, MCM-68, beta, fluorided alumina, silica-alumina orfluorided alumina containing at least one Group 9 or Group 10 noblemetal.
 17. The method of claim 1, 11, 12, 13, 14 or 15 wherein thehydrofinishing step employs a mesoporous hydrofinishing catalyst fromthe M41-S family.
 18. The method of claim 1, 11, 12, 13, 14 or 15wherein the hydrodewaxing catalyst is ZSM-48 containing at least oneGroup 9 or Group 10 noble metal and the hydrofinishing catalyst isMCM-41.